Reading Books on the iPad

If I were to buy an iPad — and I have enough barely used electronic doodads around to suggest that I just might — I’d buy it primarily as an ebook reader that I could do other stuff with. So then: how is it as a reader? Where can you get books? How many books are available? Are pages rendered as actual pages, complete with charts/picture/tables/etc. in their correct places? Are books searchable? Etc. I already have a Kindle, but I found it very frustrating with nonfiction books, and my reading these days is something like 90% nonfiction. So I don’t use it much. Should I get an iPad instead?