Originally Posted by owly
Kobo Touch can use epubs from other bookstores, Kindle can't.
Given that Amazon have the largest selection, and, generally speaking, the lowest prices, too, that's rather a red herring. If Amazon don't sell it, it's probably not available as an eBook.
Having said that, it is of course very easy to buy a book in ePub format and use Calibre to convert it to Mobi format for the Kindle. Or of course, vice versa, if you own an ePub device and want to buy from Amazon.