The day OSX Leopard came out I upgraded two of my machines to the new OS. I've blogged in the past about how insanely wonderful OSX upgrades are, however this time it has not been pretty.
Sadly, both machines have problems post upgrade. One of them can't create a Spotlight index, and I live by Spotlight, so this is a big deal. The other one hung after during an iTunes/Quicktime update. I'm sure the answer is "do a clean install," but, sorry the reason I left Microsoft OSes was so I wouldn't have to do "clean installs" and "reboot" to take care of runtime issues; please don't tell me that's where Apple has landed too.
The new Software Update facility in general illustrates a step back from the previous one. Previous OSX versions made the update process feel nice and integrated to the experience. Now you get kicked out of your session and thrown into Microsoft-like progress dialogs. Unfortunately I suspect Apple's starting to give up on identifying all run-time dependencies during update, and instead just punting (ala MS OSes) and updating the binaries once they've been unloaded from memory; whimps!
OSX distribution may just be large enough now that Apple's going to start suffering from the pains of massive distribution; namely you can't innovate as fast as you once did because you'll break things and upset users who have become accustomed to "the way things were."
I'd ask that Apple break this industry pattern by bifurcating OS development lines now rather than try to reverse mother nature's course when it comes to large-scale OS development. Let users stay on the old, un-innovative track if they want, while the more cutting edge folks can ride the innovation wave. Trying to slam the two together leads to trouble (look at the disasterous OSes that have been coming out of Microsoft for the past 12 years or so).
Don't let me down again please.