Germans are all right tbh, back when I started playing the game I only played 'murricans till rank 9, then I added Germans to that and it was all so much easier compared to the US. A while later the Brits.. recently I've also been flying Japs. I refuse to play the Soviets, they are so good against everything they're just meh, no fun playing them. I'll only play the friggin chaikas/reserves if I want to win them free eagles or something, otherwise I don't see myself playing that tree seriously for quite some time.
Anyhoo, the planes are supposedly tiered according to their year of introduction into service, not their performance, which should be balanced by the plane's repair cost (e.g. F4U-1c).