I haven't had my reader as long as some people - just two months (although I wanted it immediately!) - but so far I am entirely thrilled with it! Like many here, I am a voracious reader, to the point that "books" is an item in my monthly budget. I use it almost every day; I would switch entirely to ebooks (and ease the strain on my shelves) if not for two things:
1. Some things I want are just not available as ebooks
2. Many of the books I read are ones that my husband will also enjoy - I have to buy those as p-books because he irrationally refuses to buy a reader and I refuse to share mine
This is really the best tech investment I've made in a long time. Especially with all the tools that have been made available for format-shifting (legally), I have all the content I could want, at mostly reasonable prices, and expect to be satisfied for years.
I just wish there was more kiddie/tween lit out there - I would buy one for my 12-yr old if only there was enough available that she likes to justify the cost.