Hi Scott,
I own the original Ipad and so far have seen no reason to purchase either the 2nd or third edition of it. I use my Ipad on gigs for leadsheets almost daily and the battery life is still in the 6 to 7 hour range. I don't even plug it in on gigs - but I do make sure it is fully charged for gigs.
I can't see why folks would "give away" their Ipad for that kind of price - I sure wouldn't.
Scott, there are two main apps folks use for displaying PDF leadsheets - one is GoodReader and the other is UnrealBooks. I have both and both are very good. Each cost me under $5.00 which is a real bargain for what they do. You transfer the PDFs from you computer using Itunes. The process is not hard but does take some time to get your lists setup. There is also very good search capability in both apps when you get requests.
Let us know how you get along. For $150.00 it if you want an Ipad go for it. By the way - ask if the case is included - the Ipad is very slippery and can be dropped easily. Also, check into the "GigEasy" stand for gigs. I just got one and it is wonderful.
Deane