All iPads have wi-fi, cellular (which I would not activate initially) is an option on them and carrier specific. You'll love it once you start using it. It's small enough to take anywhere.
I have all of my tutorials on it in PDF format. I scan tons and tons of things that I think I might need on retreat. All of my manuals are on it so it's very handy to have around. I can pull it out and not have all of the weight and bulk of books to have to worry about.
If I didn't need my notebook for software for my Statler Stitcher, I think I would only have an iPad.