My new Kindle has been great.
I've only bought one book so far but read it without any problems. The Kindle's easier to hold than a book in many ways, especially one-handed page turns. Since then I've read a few M.R.James ghost stories, downloaded from Project Gutenberg, and stuck some PDF's on it (just testing).
The PDF format is not great for a device like the Kindle, you have to zoom and pan around the page, so it's treated more like a large image than a text document. However, if you set up your Amazon Kindle preferences, you can enable emailing a PDF to your Kindle account and, by making the subject of the mail "convert", Amazon will convert the PDF to Kindle format and transfer the converted document to your Kindle wirelessly. Once converted, it reads (almost) like a normal Kindle book. There may be a few odd formatting issues, but the result has been perfectly readable so far.
I have also discovered a wonderful free service that has made a huge positive difference to my Kindle experience. This is a web browser add-on called Send to Reader.
I installed this add-on in Mozilla Firefox, downloaded via the Firefox Add-Ons dialog. Once you have created a Send To Reader account and set up the service, you can add a new "Send To Reader" button on a Firefox toolbar.
Pressing this button will send the web page you're viewing to your Kindle for reading, converting it to the normal Kindle format on the way. This means that you can easily get interesting web pages onto your Kindle for later reading.
The service will obviously work best when the web page is mainly text but the results I have had so far have been great. I hope that I can push stuff to the reader this way, rather than stack lots of web browser "tabs", in the (often vain) hope I'll find time to come back and read it (if I remember). Once it's on the Kindle, I can read it in bed.
Perfect! This made my day.