Focus on what you read, the titles you like or would like to buy.
Once you validate that, check online bookstores, like Sony, Amazon, etc. Compare prices. That way, you can confirm if that device that you like so much, is backed up by a solid online bookstore too.
To me, the available books you can later buy and read, are as important as the reader that I will be using.
For instance, if you don't buy too many books or you read copyright free classics instead, which are usually free and available on most formats , pretty much any ereader will work for you.
