Just got an invite today from my brother. I think it ultimately is a better concept than Facebook, since it's not really a separate place you have to go to be social, but rather it's baked in to everything else Time will tell.
Games are won on run differential -- scoring more than your opponent. Runs are runs, scored or prevented they all count the same. Worry about scoring more and allowing fewer, not which positions contribute to which side of the equation or how "consistent" you are at your current level of performance.