My answer is quite subjective, based on what I saw during streams/matches I played:
Best players by faction:
- USA: RikerZZZ: Excellent micro-management, usage of a wide array of units, not just spamming Humvees. Spectacular air shows, good at fast attacks, good at heavy attacks.
- China: Knjaz: He invented the concept of hacker farms
. More seriously, he is very keen on massing units and rolling over his opponent. Good mig management as well.
- GLA: Jie: Constant harassement over vital points. She will drive you mad with rocket buggies constantly sniping your units/defenses. Also very good use of infantry (especially Mercenaries), for surprise attacks. A true artist in terms of psychological warfare.
- Russia: Knjaz: Very dangerous once his secondary eco is ready. He plays also by the theme of the faction here (brute force). Excellent macro-management, has a talent for mass production. Once his army is ready, it is very difficult to stop.
- ECA: Mizo: He has an almost perfect balance between attack and defense. He is very good with Claymore/Howitzer use, very hard to break his lines once they are up.
Honorable mentions (not sorted):
- (USA)Bruce: Good player with USA and Russia. He focuses on infantry management, via transports, and does it quite well.
- XAttus: Good GLA and China player. Relies more on micro-management than macro-management, making him very good in small-scale engagements. Late-game, he likes China's super heavy tanks.
- Hanfield: Good Russia player. Has some very unusual tactics, that are different from the usual "spam heavies and roll over ennemies".
- Skitt: Good ECA player. Focuses mainly on defense. He likes to set up impenetrable walls, and then use motorized inftantry to kill his opponent
- GeneralAziz: Brute-force styled GLA player. Uses Quads and Buggies EN MASSE. Problem is, he lacks "creativity". Efficient, but not as "artistic" as Jie.