What strengths do the factions have?

[Greb]

What makes the factions unique, i havent found my main faction yet

[Zesc]

Note: This is mostly DLC-focused.
Wall of text ahead!

UEF

Unique because: extra guns for everything, separate Fighters and Bombers, experimentals with the purpose of building more normal units

General:The UEF are the dumb brutes. AoE is their way of live. Their upgrades are focused on getting more bang for your buck, getting that bang delivered farther, and turning your units into their sturdiest selves.
Basically everything they have can shoot eventually, and they have probably the best economic buildings in the game.
The main playstyle is all about dominance. You try to get air or naval supremacy with your specialized hunter killers (Wasps and Tigersharks) and then harass your opponent with the other stuff.
Their ACU is... meant to be a frontline engineer sort of thing? It hardly ever works out to upgrade it.

Best units:

• Wasp: Affordable Fighter, can out-spam Fighter/Bomber hybrids of other factions.
  
• Tigershark: basically a swimming wasp.
  
• Fatboy Ⅱ: The mobile unit with the second longest range in the game (only outclassed by Cybran Battleships); can devastate armies before they even reach it.
  
• AC-1000 Terror: When properly micro'd can outrange most AA.

Aeon

Unique because: they have no navy but hovering land armies instead, teleportation, shields reflect attacks, combined Land/Air gantry

General:The Aeon are specialist, lacking general-purpose units. They also are good at hit'n'run, because they have good shields and plenty of ways to regain lost HP.
They got this whole "hovering" gimmick which is actually pretty decent once you get used to it.
I believe they are the hardest to play out of the three factions, as you need to know what your opponent is doing in order to find the proper counter.
Their ACU is a nasty, evasive b****. In a 1v1, this only means delaying the inevitable, but in bigger games you actually get chances of fleeing and rebuilding with it.

Best units:

• Harvog: The AA upgrade on these guys is seriously insane, and with two upgrades to shields and damage, they become awesome raiders.
  
• Wilfindja: Highest land speed of all units, mobile radar/sonar and packing quite a punch on close range.
  
• Tactical Missile Launcher: having these as cheap stand-alone versions is great for targeting vulnerable infrastructure in the back.
  
• Point Defense: this thing has more range than the other PDs so it is excellent at securely creeping forwards with forward bases.

Cybran

Unique because: they have no tanks and start with assault bots, walking ships, kamikaze attacks

General:As they complete opposite to the Aeon, the Cybran have many jacks of all trades on their disposal. They live "offense is the best defense" as their upgrades focus on giving your enemy no time to breath.
The thing about their upgrades is that they are either very, very good, or a complete waste of Research.
Your whole gameplan will be aggressively pushing for the strong stuff whilst trying to cripple your opponent's expansion before they can bring out the big guns. They are considered to be slightly stronger than the other factions in competitive play, but not to the extend where they become an undefeatable steam roll. One wrong move, and your opponent will be able to penetrate your barely-existing defences and make your life hell.
Their ACU can get absurdly strong, casually soloing experimentals. You can basically play Dynasty Warriors with that thing when your willing to dump enough RP.

Best units:

• ADV Adaptor: Stacking shields, Anti-Missile (TMLs are one of the things good at breaking shields) and AA on the same unit makes it worth its cost. A bunch of these grouped together around something with good weapons is just impolitely powerful.
  
• Megalith Ⅱ: The Megalith's main strength is its lack of weaknesses. Good range, good attack power, decent speed, AA and a respectable health pool mean that everything trying to kill it has to earn that privilege.
  
• Bomb Bouncer: This, paired with ADVs and the DLC-exclusive Cicada is just excellent for death-balling your opponent. Far away attacks are tanked, and anything up close gets blasted.
  
• Long Range Artillery: The simple fact that this thing has a RoF upgrade makes it way more terrifying than its UEF counterpart.