But on a gig, you got power. If that's what you primarily use it for (what other use has an MPP?) where's the problem?
Though I concur that there's typically already power required for the rest of your rig at most gig venues, I really appreciate not having to drag along yet another power cord around to gigs. The iPad can run up to 10 hours on a battery charge. Without a power cord attached, the iPad can conveniently sit anywhere and be easily moved about on stage without distraction. With my Tyros 4, I leave it sitting next to me, and then quicked grab it with one hand and leaned in front of my Tyros 4 LCD screen when needed, and then just as quickly remove it, when not required. All this time, the audience doesn't notice the iPad, because its not in the audience line of sight, and partly because theres no power cord attached to it to call attention to it. The MPP, laptop, or even a netbook, don't offer this kind of on stage convenience, lighweight flexibility, device size discetion, or the level of outdoor viewability the iPad offers. JMO as I own(ed) all four.