I bought the family pack for Leopard to upgrade all my machines back in November.  I was waiting, however, for the first big patch to be released before I did the upgrade (I am an earlyish adopter of tech, not a bleeding-edge adopter) because I just didn't want to deal w/ glitches on my work laptop. Well Apple just released 10.5 update  BEAST (all 347 MB of it !!)

The standard upgrade went well (I did back up my data to and external drive) and took about 1 1/2 hours. Then I went into work to download the BEAST and with Sun's big pipes that took just a few minutes (less than 5, I think).  I ran the installer (another 5 minutes or so) and it worked great.

 Now, After 24 hours, everything is stable and I've noticed no problems.  Nor have I noticed my Mac running any slower or faster - its just about the same.  All programs work, all data is there, none of my documents or pictures were lost.  I had 2 very minor issues 1) I had to reinstall my printers and 2) I had to reinstall PocketMac to sync my BlackBerry.