Best IOU APP?

So ive been trying to find a REALLY good app to help with basically IOU'S for when i lend out money, stuff or if i borrow from a bud.

I used to used one called IOU on my GNExus that had a drop box back up..

Is there any apps you guys can recommend on IOS that does this? Preferably with some type of cloud back up?

So many apps to chose from in the app store. Any highly rated ones you can advise?

And yes... i realize "google is your friend".. but there are so many apps like that.... at this point i would like advise fro someone that actually uses one?