Interesting discussion ... I won't argue that a laptop is easier to type on, and has plenty of great software, possible uses, etc. I own a laptop too. I just chose to use the iPad I already owned, and (as in the note a while back in this thread), I found that with some "prep work", it works very well for the way I use it at gigs.

When I do a solo gig, I use prepared "set lists" to get started, then if the audience (via request or my "judgement" of how they are responding to various songs) wants something "off-set-list", I can call it up in seconds. And the iPad sets up my Tyros too (via Registration links). I went straight from physical music books and lists on pieces of paper, to iPad (I didn't happen to try/use a laptop on stage).

At band gigs, it's about the same, plus the "master/slave" thing I described. It's not perfect - once in a while there is a glitch or something, but that's rare. And even with the "on screen" keyboard, I can call up most any song in my ~1100 or so song index, with just 3-4 characters (If I want to call up "Hotel California", I just do a single tap in the upper left of the screen to bring up the Search field, then I type "cali" - and there it is - tap the song name, it loads the PDF for the song, and sets up my keyboard, I'm ready to play. And the band members see "Hotel California" come up on their iPads.

unrealBook is definitely in the Apple store (app store on the iPad), as I helped my bandmates purchase and set it up etc.).

Hope this is helpful info,
Jim