Just my observation
I went Mac back in Panther. Started reading the Apple forums right away. Panther was brand new.
Since Panther, and Tiger, and now Leopard, it seems Apple has followed a horrific predictable pattern.
In a nutshell, it's this: The first 3-4 releases of any OS are bugridden and unreliable, and give early adopters fits.
Round about the middle releases, X.X.5 to X.X.6, they get stable. Finally.
Then the following releases are all nightmares, UNTIL THE VERY FINAL RELEASE, which usually comes extremely close to the release of the new OS.
Now, whether you want to blame this on Apple rushing in all sorts of hooks for the new OS in the old OS, or absolute malfeasance (screwing up the later releases on purpose to make more people buy the new untried unreliable versions when they first hit the market) the conclusions are the same:
1. STAY AWAY FROM ANY NEW OS RELEASE until midterm. This is an absolute must.
2. STAY AWAY FROM ANY NEW OS UPDATE until the very final version is released. Ignore everything after the stable midterm release until the final version is released.
3. Then STAY ON THIS VERSION until the new version is at midterm.
If you follow this procedure, as I have from the very beginning, you'll avoid being an unpaid beta-tester for Apple. With the accompanying disastrous consequences.
As for me personally, I'm still not even remotely interested in Leopard, yet. In fact, I probably won't bite the bullet on it until Snow Leopard is released and I can be assured they've gotten out all the bugs out of Leopard and the pre-Snow Leopard disaster releases (like THIS one) are finished.
This strategy also makes sure that all 3rd party drivers have been caught up as well.
For what it's worth.
P.S. I'm not even running Spotlight via Spotless, so in that way I'm still on Panther, even though I'm on 10.4.11. My hard drives thank me.