I would want to know what the Facebook functionality would add to my experience besides the login ease. Signup is not really a major hurdle for me such that I would feel more comfortable with FC in place. In fact I would be less at ease because of my Facebook privacy concerns. My issue is more about the complexity of the site but perhaps its just my prolbem - just wanted to let you know my gut reaction. I visited, looked around, got confused and frustrated and left. It seems like you're trying to accomplish a lot - maybe a tour video would help. Or paring down the features/UI.

Take it with a grain of salt. I'm probably just an idiot.