Unfortunately, my somewhat mixed feelings about the new OSX 10.5 Leopard release have taken a turn to the worse. I'm now very much inclined to agree with Dave Winer who wrote:

this is not a good operating system release.

In my case:

• For the first time in living memory, OSX actually freezes.
• After freezing, Mail.app loses 80% of my e-mail in-box.
• Time Machine, which is supposely backing things up continually, shows me the content of the old mailbox, but then fails to restore more than 3 messages from it.

So: if I do not respond to your recent e-mail, please resend — you know now why.

And there are plenty of other problems:

• Skype doesn't run as long as the OSX firewall is on. (Come on guys at Apple, you can do better than this!)
• Nobody seemed to have done any testing of Spaces with Java. For that matter, testing of real-world Java apps seems to have been under-resourced. (to put it mildly)
• My iSync application refuses to start at all. (Console says SyncServer[339]: fatal error during sync server initialization: can't upgrade data directory from version 47 to version 75 (/Users/jernst/Library/Application Support/SyncServices/Local) What am I supposed to make out of that one?)
• Addition: Google Earth crashes during the launch, too.

My advice now: stay away from Leopard. It's not ready to be used for anything serious, and I regret that I upgraded.