Openfeint or Facebook?

First of all I'd like to introduce myself - my name is Piotr and I working at iFun4all - new developer from Poland (so please forgive me if I am making some language' mistakes).

I read many things about social systems at TA board and we are right now choosing between Openfeint and Facebook. What do you think should work better? I know that Facebook has much more people but I can't see as many games with Facebook connection as with Openfeint.

Thank you