I was lucky enough to get a Kindle soon after they were launched in the UK, so have had a few months now to use and assess it. The considered verdict is that I still love it. Initially I was unsure about how I would enjoy reading on screen, but I find it very easy on the eyes, in fact I think I actually read faster on the Kindle than I do from a paperback book.
One of the downsides of reading on the Kindle is that, unlike printed material, VAT is charged on ebooks and the VAT rate has just gone up to 20%. Partially perhaps as a result of the tax anomaly, Kindle books are in most cases not much cheaper than their paper versions, despite the fact that no trees were killed in their production. Ebooks do, of course, have fixed editorial and set-up costs, but most of the variable costs, other than royalties, of printing and distributing a physical book are lost, so I don't really understand why there isn't a bigger discount.
For anybody existing on a very low fixed income, the cost of even a paperback book has to be a seriously considered purchase nowadays. I'm therefore taking full advantage of free Kindle books and low cost promotions, such as the selection of books for £1 each Amazon offered over Christmas, but my purchase of regular priced books has not increased too much, despite the undoubted convenience of the one-click Kindle store. I have to restrain myself.
A huge benefit of the Kindle is the ability to download free samples of books. I have over a hundred on my Kindle now. Some of these samples are of books I would like to buy or borrow from the library one day, a digital wish list, if you like. Some are for reference, to enable me, as a writer, to analyse the first few pages of a book I don't really want to read in its entirety, just as I sometimes do in my local library. Some samples I just download for curiosity's sake and fairly quickly delete from the Kindle. I have already downloaded a couple of books just on the basis of having been totally hooked by the sample, Sarah Rayner's One Moment, One Morning being one of these.
I find it hard now to remember what reading was like before I had the Kindle. It could never totally replace printed books, as its back and white screen cannot translate illustrations and photographs well, but I do find it easy and convenient for fiction and some nonfiction. I also use it to store some personal documents, such as lists and pdf crochet patterns, though I haven't yet dared put my novel on it!
I'm a total convert to digital books, with the proviso that I will still buy physical books too. Best of both worlds, really.