Some of us spent much of the weekend tinkering with the OS X 10.6 (released Friday).
I did a straightforward upgrade install on my least-critical (and oldest) computer—an early Mac Pro Core 2 Duo system—on Friday. The install took roughly 45 minutes (unattended) then asked to reboot. I consented, it rebooted and hung on a blue-gray screen (mouse and keyboard worked, but there was nothing to do). I did a hard reboot from there and the machine booted correctly and has since continued to function as expected.
I've been testing all the software I've got, and so far, everything has worked fine. Even the ancient Gretag Macbeth/X-Rite Eye One Match software and hardware appear to work. The only problem I've encountered is that my test print from Lightroom to my Epson 3800 came out too dark, suggesting something is amiss with my color management and/or printer profiles. I hope to investigate this problem further in coming days.
Lloyd Chambers has been a testing demon this weekend and he has an
ongoing-writeup reporting significant performance improvements pretty much across the board.
Generally speaking, Snow Leopard is looking like a no-brainer upgrade for the photography community, but that doesn't mean you shouldn't exercise caution about upgrading too early. I strongly recommend installing 10.6 on a non-essential machine, first, or waiting until the first point release before leaping in.