I'm on my second kindle now, and in between the two I had the Nook. There was nothing wrong with the first Kindle, it was stolen at a hotel on a business trip though, so I bought the Nook.. used it for a little while, and then bought the Kindle again.
It revolutionizes the way you read, and it's completely worth it if you spend that much time reading. It's obviously incredible for anyone who's job has them traveling a lot. Best sellers for 9.99 is a nice touch though, and how light and easy it is to use is a lot better. The global internet, and wikipedia is good too.