Amazon recently banned a customer for making what they considered too many returns, and when they did this they also disabled his Kindle account, although the returns were never related to Kindle purchases.
I had no plans to get a Kindle anyway. I prefer the smaller size of my Palm Tungsten, which allows me to just stick it in my pocket until I have some time to read. But the DRM issues would also keep me from considering it. There have been too many instances where companies have turned off their DRM servers, leaving their customers without the goods they purchased.