Using the built-in "update" feature of WordPress, to update WordPress itself or my plugins, is extremely slow for me. Updating WordPress can easily take half an hour.
Just now, I upgraded to WordPress 3.0 (I did that update using Subversion); then I used WordPress's update feature to update my Akismet plugin. I didn't time it, but I think it probably took about 15 minutes to update Akismet.
Any idea what might be causing this?