A lot of people are complaining about features in Mac OS X Leopard being buggy. And, they do have a point… some features are buggy. However, I think people are missing an important point: The vast majority of issues are surrounding features that were not in Mac OS X Tiger.
For example, there are significant issues with Time Machine. It does bug out at times, it has trouble backing up over the network, and yes, Apple should carry through with demoed AirPort Disk backup. But, was Time Machine in Tiger? No, people were left to fend for themselves to backup. Does A2DP Stereo Bluetooth work well? No, it doesn’t. Also not in Tiger. Is Java 6 missing? Absolutely… but it was only a developer preview for Tiger.
My point is, you shouldn’t fear upgrading to Leopard. You shouldn’t fear 10.5.0 just because it hasn’t clocked over to 10.5.1. Rumors of new directory issues are not really founded (though some issues that were supposed to be fixed in Leopard from Tiger still aren’t). Apple throughly tests these upgrades, and any show-stopping issues are fixed quickly… and were within 48 hours of Leopard’s release. I watch people, who do not regularly backup, say “well, I’ll wait for them to get the bugs out”. I just can’t shake the fear that I’ll get a call from them saying “my computer’s not starting up, please please get my files back for me”. Especially with potentially faulty hard drives lurking in half the Mac fleet… my response is: Get Leopard now, turn Time Machine on, and use Mozy as your backup for your backup.