Overview
Getting a grip on all the units can be a hard especially with the 3 different upgrade paths (1 per affinity) and dozens of selectable perks. I will try to give a short overview of the Units and Affinities so you can better guess wich ones to work towards and wich not and whose factions warfare style fit you the best.Note: The changes of the December 2014 update have not yet been worked in.
Affinities, Unit Upgrades and Warfare styles
Harmony:
Harmonies strength is the ability to get bonus from Miasma – inlcuding passive healing. Since miasma aids them but hinders non-harmony foes, they can be quite powerfull in defense and area denial.
Thier unit upgrades focus on healing, better combat while in miasma and “bonus when not having friends nearby”.
Thier Unique units are Melee only, with the exception of the Rocktopus.
Purity:
Purity focuses on raw power and the ability to take cities. With purity it goes “strike first, be the only one still around and kicking”. They are especially good against aliens, taking cities and defending cities. Purity does not go for situational modifiers, it goes for raw strenght especially in offense or defense.
Thier unique units favor Artillery and Ranged Combat like no other Affinity. In turn thier range does not upgrade as easily as others (requiring a perk and/or not moving in many cases where others get them it for free).
Thier first two unique units use Titanium as main resource, meaning they can field exceptional amounts of T1+T2 units in most situations.
Supremacy:
Thier strenghts are mobility and versatility. For example thier final Gunboat Tier has the ability to work as small carrier.
In offense they win by outmaneuvering and flanking the enemy more then via raw strenght. They are also strong in groups and in thier own territory. In defense they can also benefit from cost-free magrail and road connections. In offense they have to rely more on zerg-rush then other factions.
Thier unique units mix ranged and melee abilities and includes the most longranged artillery in the game.
Mixing affinities:
It is possible to mix affinities however you want, but this has ramifications for the unit upgrade process.
For the basic units you need a high primary affinity to upgrade. You will not get T4 Soldiers before you have reached Affinity 11 in a single affinity.
Affinity units are a bit differently, as some affinity from other paths can be “mixed in”. The affinity 4 units get an upgrade at primary 12. Or Primary 10 +2 in other. The mixed ones have one chooseable perk that is more fitting to the secondary affinity (a 12 harmony+3 Purity xeno swarm has a perk to make unused movement into combat strenght, for example).
Also note that each affinity level that is not your primary affinity suffers increased cost equal to [current level]-2 times 2. Making it very hard to reach higher levels needed for unique units when already having a different primary affinity.
Basic Units
Soldier:
The first unit you get. While they have the ability to fight most aliens in melee, thier primary role is meatshields or roadblock and to capture cities brought down by ranged units wherever the unique units were not avalible for the same job.
They are inferior to the starter unique units but upgrade nicely.
Ranger:
Aside from the Unique units perhaps the most powerfull and versatile unit in the game. They are your first ranged units, capable of whitling down even siegeworms and cities as long as you have enough mass.
In the defense they depend heavily on terrain modifiers. Either shield them with Melee units and/or put them on hills and in forrets (later is adviseable against cities and ranged foes in particular).
2-4 of them can siege down a lone city and take it’s fire until the melee units can march in.
They also make a good garission for cities having the same attack range as it.
Rocket Rover (Artillery):
In theory those are supposed to be the primary weapons to attack cities, having significant bonuses towards attacking them. In practice they are heavily hindered by being only as fast as Rangers, but also having a setup time. Also you likely already have T2 Rangers by the time you have them.
Basically they work like rangers, just less mobile, with minor anti-orbital abilities and some bonus against cities and more expensive. Until they got Tier 2-3 upgrades they are hardly worth thier money.
Suprisingly the lower version can be very good at defending your cities, where thier lack of mobility is not an issue and where thier superior firepower can make a difference. It is worth a try to focus them towards bringing down units in such a role. If you have the spare time to build them, consider using those as garision rather then rangers.
Combat Rover:
The Cavallary and raiders. While they have quite a bit of combat power it is often cheaper to use marines and the Unique melee units as meat-shields or melee attackers.
They are often better used for hit-and-run attacks on the enemies or strategic pillaging, raiding and roadblocking.
The final upgrade allows them to float over water, making them the primary melee unit for naval warfare once that happens.
Tacjet:
These are basically ranged units with exceptional range. Thier big downsides are they they can be intercepted, always take melee damage during attacks (unlike other ranged units), need a base and propably need other units scouting for them.
You have to decide if you have more need for a bomber or interceptor when choosing your upgrades. There are 3 jobs your Airforce can perform:
Intercepting attacks enemy figthers on strike mission before they reach thier target.
Strike attacks enemy gound and naval targets
Air Sweep draws out enemy interceptors so they “waste” thier interception on the wrong targets and can be shoot down.
They are especially valuable at getting Naval superiority if placed on a carrier. On land it is often better to use them as interceptors and for the ocassional longrange strikes. There is no landbase for them other then cities, producing a kind of “Airforce gap” for the attacking force.
Role of Airforce: A lot of cofusion exists about what to use tacjets for. Generally they are a bad choice to deploy against meelee units. However they fare execelent against other ranged units, being able to outrange and out damage nearly any other ranged unit. They can also prevent your ranged forces from being picked off by enemy Tacjet’s.
Gunboat:
The naval counterpart of the Ranger. However a lot less powerfull then thier land based counterparts.
They are highly vulnerable to alien melee attacks – or just about any attack. While they can provide anti-land artillery support, they take heavy damage from cities, air strikes and other ranged units. On top of that ships do not heal while outside of your Borders. Without terrain and some meatshields they are about as usefull on sea as marines are on land.
Unfortunately they are also the only early game naval unit. Pick your fights carefully.
Carrier:
If you want to control the seas, they are a way to go. They have no attack ability, but instead work as swimming base for Air units.
However they are incredibly durable. They do not need gunboats as escorts, they need them as scouts.
Thier weakpoints are that they are midgame, quite expensive in upkeep (you have to include the cost of the Air units) and need cities to replace lost fighters.
Note: Only basic unit that has only one Upgrade Tier.
Affinity Unique units
Affiniteis have 4 unique units, that unlock at affinity levels 4, 7, 9 and 12.
Thier big downside is that they cost the Affinity resource (and sometimes other ones) to build. That means you have less resources for affinity specific buildings cosuming the same resource.
Also you have to distribute the affinity resource amongs all the Affinity units, meaning that they can be a rare sight on any battlefield and you might have to delete some low tier ones to be able to build higher ones.
One upside is that unlike the basic units you can easily “blend in” other affinity levels when upgrading, unlocking perks that are more fitting for the secondary affinity.
Upgrades at Affinity 12 or 10+2
Xeno Swarm/Battlesuit/CNDR:
This unit is about the same for all 3 Affinities – a powerfull melee unit. They outclass just about any other unit of thier time in combat prowess. They can engage any Basic units with barely taking any damage, take quite a pounding from ranged attacks when having terrain modifiers and even attack cities or siegeworms in melee and make headway.
Effectively they play like Tier 3-4 Marines, except they are availible much earlier. They strongly loose power once marines have comparable melee strenght however, so it might be wise to replace them with those and use the resources on more powerfull unique units.
Note: Batlesuits are special in that they need titanium, not floatstone (the affintiy resource).
Upgrades:
Xeno Swarm +20% in miasma with a common perk for another +40%
CNDR get’s +8% per adjacent unit and has a common perk for +30% in own territory
Battlesuit: Battlesuite get’s +30% in defense and a common perk for +20% when flanking
Upgrades at Affinity 14 or 12+3
Xeno Cavalery:
A more powerfull brother of the Combat Rover. It stays more powerfull then even the T4 Rover, but lacks it’s hover ability.
Upgrade: All tiles 1 Movement + common perk for +40% in miasma.
Aegis:
A more powerfull version of the Ranger and as versatile as those. No need to set up, powerfull ranged attack and relative durable when under fire. It needs a combination of Titanium and Floatstone.
The Upgraded version can attack twice per turn, can move after attack, heals nearby allied units by 20 HP and has a common perk for +40% against wounded units.
CARVR:
Works like a beefed up CNDR, meaning it stays superior even to T4 marines. Upgraded version has +15% when ally nearby and a common perk for another +8% per nearby unit.
If you can afford to purchase one per turn, 2nd best supremacy unit to send into Emancipation gate.
Upgrades at 16 or 14+4
Rocktopus:
Re-useable, semi mobile orbital kill sat. Is not deployed like normal satelites. Floats on ground level to the target tile, then jumps up into the orbital layer. Only vulnerable to anti-orbital strikes while on ground or in orbit.
When send to orbit is stays there for it’s orbital time, cannot move but can attack like a Orbital Laser/Planet Carver. It returns to the ground level after it’s time is up (and at will with the proper superiority blend perk).
Firepower between Orbital Laser and Planet Carver. Upgraded version also works as a Miasma Condenser while in orbit. Also needs floatstone.
Lev Tank:
A floating ranged unit without need to set-up, but with orbital strike. A excelent combination of ranged damage, mobility and durability.
Upgrade: +10% per unused movement and common perk for +1 Movement.
SABR:
Longest ranged artillery (3 Hexes base range).
But it suffers from a setup time and having only 1 Move. And it cannot fire over obstalces by default (but learns this with the upgrade). It seems to be designed primarily as defensive unit, where it’s downsides are not as relevant and it works like a beefed up missile rover (inlcuding being usefull as garission).
In attack it heavily relies on having a road or magrail connection forward or starting close to the target.
Upgraded version has +1 Range, can shoot over obstacles and has a common perk to remove the setup time.
(Ultimate unique units)
Upgrades at 18 or 16+5
Xeno Titan:
The ultimate melee unit. Is best engaged in ranged attacks but can take a lot of those too. The upgraded version has 114 Strenght, +50% ranged defense and heals 20 HP when killing a unit.
It is the only ultiamte unit that has to work through hard terrain and can be delayed using sacrifical units or not-cleared swaps.
Think Star Craft Ultralisk. Or Godzilla.
Lev Destroyer:
The Ultimate, floating artillery unit. Has exceptional melee power, making it very resistant to enemy attacks for a artillery. Must be set up and still cannot melee attack.
Upgrade: +30% Attack, 10 HP Splash damage, commom perk for +1 Range at full health.
Angel:
Supremacies ultimate is supposed to be a multi-role unit, a 1 Hex Ranged attack without Setup, Melee attack and the ability to cross chasms and coastal water. But is not a floater (has to embark for deep water; no “1 move per sqaure” by default).
However it is currently not able to melee attack, making it only very resilient but shortranged ranged unit. If you can afford to purchase one per turn it is also the best supremacy unit to send through an emancipation gate.
Upgrade: 102 melee&ranged strenght, can move after attack, all terrain costs only 1 and common perk for +30% when attacking