Mobipocket, LIT, or Kindle - which is best?

[daddydave]

If I have a choice of buying a book in Mobipocket, LIT, or Kindle format, and the prices are similar, which should be my preference? In case it matters: some of the books I am interested in may have a fairly complicated layout and I will be reading on an iPod Touch.

[Self-edited for abrupt shift from third to first person]

[daddydave]

I came to know that Amazon has a 7 day return policy on Kindle content, which is good to know -- the other ones I am not sure about.