Last weekend I went for Serendipity software version 2. This caused lot of downtime as the upgrade didn't go smoothly. I also made the entire server almost choke to a crash as my .htaccess / mod_rewrite -trickery caused looping. My Apache tried to loop itself into an exhaustion.
After I got everything back into shape, I got new toys. Especially the back office -side is vastly improved. On the public-side it seems pretty much the same.