This is my list of best units in the GAME (not to be confused with the real world )
Best transport helicopter:Russian YAK-60
Best fixed wing transport :American C-130--- corrected to 747
Best artillary : Chinese
Best Anti-Tank:All region BMV -exact model depends on circumtance.there are 3 to choose from
Best Sub : All region Man of Steel.
Best Fighter: My opinion on this varies ,but id say the American F-22 , the American F-121 Aurora,or the Japanese Fi-6 Gac.
The f-121 and Fi-6 are really fighter bombers, but they do such a killer job as fighters i often use them for such (when im not carpet bombing and destroying my foes with missiles
Best Tank:American M1090 FCS,but keep in mid that this unit has less than an 8% advantage over its competitors(stat wise).
Best Mech Infrantry:Multi region LAV-5, but closely followed by the All region IFV-1 Crow ,the multi region M118A2 APC
and the multi region AV86 Terrax.
Best Foot infrantry:Hard one to call,my favorite is the multi region special forces II unit.Its got incredible close combat stats .Something you dont want to run your expensive hard target units into in a close combat hex.
Best bomber: American B-52H- if your just looking to do damage
----------------American B-2 -if your also worried about being attacked while doing your damage.
----------------And my overall favorite bomber unit in ALL circumstances the American X-45A darkstar ,closely followed by the multi region Nueron.
Now i must confess, i havent given the non-american bombers a good look in the game.So i might not be giving the bear,backfire,squall,etc.. their due, has i havent used any of them in a long time and dont remember their stats.
Best Carrier: doesnt really matter as they dont work right and hence lose much of their point in the game.
Best Large Attack ship (includes battleships,destroyers, and cruisers):American Zumwalt -this ingame ship received a combo nerf and buff sometime back, but still remains the best all purpose attack ship.
Its closely followed by some of the american and european battleships and cruisers though.
Best Attack Helicopter: Dont know, dont use them very much due to issues.Damn heli pilots