I would say obama has the advantage in a format like this, especially with (once again) another life long democrat that loves obama and wants obama to win, who has said she has a right to "edit" the questions as she sees fit.
Obama is better (or perceived to be) at relating to the takers. Note that every question tonight will be some variation of "my life sucks, what can you give me?"
The one problem Obama has in this debate is that he needs to start driving hard at Romney and being aggressive, but with this type of format it's hard to consistently attack a candidate when you are really speaking to the audience. So I think that handcuffs him a little bit.
I think Romney just needs to not say something stupid. I think a tie is a win for Romney, so Obama is going to need a decisive victory, and one that actually slows or reverses mitts momentum.
If obama loses this debate in the eyes of the public like he did the last one, I think it's all over for him