I play this game a lot. I agree about china being superior. However, I do love USAs airforce (very fun to use). Nothing beats Chinas bunkers full of rocket guys and a few gatling guns for defense. Mows down angry mobs, etc, and USA cant flashbang the bunker. Sometimes I just build 10 nukes and kill my enemy that way. I don't like losing guys in battle. Against USA I use my EMP, then go in with Lotus. I use my general promotion points this way, save them up till level 3. then get lvl3 artillery, and EMP when I am level 5. Then the rest is up to you. Maybe get medium repair etc. Also, one superweapon never takes out another, it always requires either a10s or artillery along with a superweapon. However, if you are playing against, say, China and they have a nuke counting down, and all you have ready is either a10 or artillery, then go for their power. They may have 2 nuclear power stations together, and the artillery will surely take those out, then the nuke won't have power. Just do whatevr works.
If you play as USA, Col burton kicks ass with advanced promotion. When he is level 3 a gla stinger site dies fast. I could go on and on. PM me if you have any questions.