The major e-bookstores from an international reader’s perspective:


Amazon: Amazon is the gigant in the e-book business ( with all the good and bad things that comes with it). For some countries they are the best source for e-books. Best prices, and the biggest sortiment. I’ll admit that I download free reads to Kindle for PC, and then transfer them to Calibre ( thanks to third party plugins, I am able to open up the encryption), and the convert them to epub.  The thing that stops me from buying books is the fact that Amazon adds 3 dollar to the price, supposedly tax but honestly 2 dollars tax on an 0.99 e-book? Uh. No. I know that VATin most European Countries is 20%, and 20 of 0.99 isn’t 2 dollar.   Also, Amazon are inconsistent, sometimes they add the fee, some times they don’t.

BN:  BN, unfortunately, is US only.  Which annoys me, but I accept it. Until recently, I used to be able to download free e-books from them, but that stopped.  Interestingly, about the same time I read that  Barnes and Noble is about to launch Nook internationally.  Uh-uh. If so, it is good if the new Nook owners are available to buy from BN. 
Kobo:  Kobo is Canadian, and I used to shop there a lot.  They frequently offers coupons, and discounts. What made me stop using them were several things. They started to add taxes to the prices. ( I understand the reasons behind them, but I don’t have to like it)  There were also other things, like the fact that their search function is bad, they don’t have a cart or a wishlist. Minor, but it get  annoying after awhile. It does happen that they have a book that I want, for a good price.

Booksonboard:  I switched to Booksonboard from Kobo, and I must say that I am happy.  Their prices includes tax, the sortiment is good and so are the prices.    Oh, and they have a cart and wishlist function too.   The only thing that annoys me is the fact that some of the older e-books  only are available as pdfs and Ms Reader.   Beyond that I am happy with them.