I have successfully upgraded all my personal/business web sites to WordPress 2.1. I ended up doing clean installs on all my sites (it had been awhile) and only ran into one problem with the plugin PodPress. If you are using WordPress, make sure you check out the new version!
[...] okay this exciting analysis at http://www.jappler.com/blog/archive/2007/01/23/wordpress-21 about [...]