Hi
I lost as USF and won as OKW, both games were four faction games (i.e. mixed teams).
Here's the thing - I felt the games were well-balanced in terms of player skill (I'm out there in the not-very-skilled majority) but I played better in the game I lost (i.e. USF).
Why?
Because USF offers nothing over soviets in team games, you are better off the more soviets you have on your team. All the weaknesses the USA faction already suffers from in 1vs1 after the first 8-ish minutes of the game are magnified in team games while their strengths are reduced due to increased unit density on map.