Using i-Pad to hold sheet music (tab)

Do any of you use your i-Pad to hold your tab rather than carrying multiple notebooks full of printouts with you to practice or a gig?

I am trying to decide which is the best app to use for this, and would like advice from anyone already using one. I found an app called GigBook which looks pretty good. But before I buy it, would like to know if there is a better one?