Thanks for the welcome and the suggestions. Unfortunately, the Kindle is not available in Canada and even if I could get my hands on one, the network needed to download the books doesn't exist here. The Sony also is not available in Canada. Someone has suggested that I try the EB-1150 as it apparently is very ergonomically designed. Although it doesn't have e-ink, the ergonomics are the most important consideration at this point.
The buttons on my Cybook (I had a Gen3) did loosen up with use but they still caused wrist/thumb pain. I can't blame it all on the ereader, I'm no spring chicken and things just don't work the way they used to.
I gave the Cybook to my 25 year old daughter who loves it and is having no trouble with her wrists. LOL