>>133616TSMT, I have played most nations ground up to ~3.0 and have gotten both Japan and France to about 7.0, after that point the game starts being too grindy to be any fun. Its a lot more worth it to play another country's low tiers than to force trying to reach high tier.
I will probably play france until I get a bit higher because I like the oscillating turret tanks, but otherwise I don't see any reason for me to grind past 7.0 with any nation. Top tier gameplay in both ground and air looks ass, all MBTs play too similarly and missile fights look boring.
If OP only plays air, I would highly recommend Japanese prop planes, the guns are a bit anemic but they're so maneuvrable.