Epub obviously isn't universal if not all ereaders can read it
I have and love my Kindle, I've read about a lot of issues with the Kobo (I almost bought one when Borders was going under but didn't) and again, from what I've read, their CS isn't nearly as good as Amazon.
Pick something like 10 books and look them up on both Amazon and whatever Kobo's site is to compare prices and availability.
Amazon also just came out with 3 new kindles so there is definitely a lot of options whether you like touch screen, keyboard, or just a basic navigator button.
I honestly can't say enough about both Amazon's CS and the Kindle itself, I bought one for my sister and my mother in law, and in general recommend them to everyone I know
