I use the Kindle app for most of my purchased reading and while I love Stanza it was a pain having to split my collection between two apps. (Especially for stuff I buy from Webscriptions). I keep my Calibre library in Dropbox so it was nice to see that open in Kindle option appear for mobi books
I am surprised there's still no update for magazines and newspapers though. It would have been nice to get an automatic delivery of Asimov's