Haven't read through the entire thread, but here goes.
I used to be very biased towards playing Axis for the following reasons.
1. Ostheer is much closer to vCoh Wehr than Soviet to any vCoh faction. Familiarity alone made them the more appealing faction to begin with.
2. Axis is the comeback side. We all know how difficult it is to dominate early game axis and usually you are just holding on till late game. This appeals to me as the wins are more satisfying when you overcome difficult obstacles early on to win the game.
3. More interesting (and famous/infamous) weapons and units.
4. Playing the bad guys.
5. Since I played almost exclusively axis and I enjoy being competitive, learning the allied factions was somewhat intimdating since I knew I'd be such a noob.
However...
I now play allies probably more because.
A. The wait times aren't ridiculously long in que.
B. Turns out, the Soviets are pretty damn fun with some variety of their own in units.
C. I'm an American and want to play with units of my country. (Shameless plug)
D. It gets boring playing only one side.