Germany ain't bad with its 15% damage bonus after a win, not to mention more options for strategy with longer rallies and a lower cooldown before you can use them again.
I am currently playing as Greece as it has suited my way of play, but with the completion times stretching out for so long now this is not longer a perk that has any substance.
The thing is the game is constantly changing and evolving, so I'm anxious about making a jump to another nation. They need to buff up Greece before most people ditch it for something better, does anyone expect it to happen in the near future?