I have looked again at the Kindle eReader. It seems that they have upgraded the software so that it now reads PDF files natively instead of having to run them through a conversion process. That makes it much more appealing.
And Amazon has over 340,000 books available. So it seems like the combination of Amazon and Kindle is the best overall situation.
As a side note there is a book I have been trying to buy for several weeks but isn’t available due to being sold out. But if you want the ebook version it’s available right now. Another reason to get something like the Kindle.