I picked up my family pack of Snow Leopard on August 28th - the day it came out. I have been reading about it for months and the feedback had been predominantly positive so why wait?
First upgrade was my laptop. I didn't bother to close down any applications, I just popped in the CD and a few mouse clicks later the upgrade was in motion. Almost precisely 40 minutes later Snow Leopard was up and running. Immediately I opened a bunch of apps and tried some of the new dock and expose features. Everything worked wonderfully. The final test was to leave all those apps running and see how fast it shut down. This was a big improvement! I took about 7 seconds to power off - that is way, way faster than before.
Saturday afternoon I upgraded to Snow Leopard on my iMac. Again, just a few mouse clicks to get it running and about 45 minutes later it is all done with nary a glitch. Impressive. I have used and supported Windows since the very early days of that operating system and I have never had an upgrade go so smoothly on one PC let alone two.
The biggest Snow Leopard changes were under the hood so not much new stuff was readily visible after booting up. I had read about a bunch of tweaks and improvements so of course I gave them a quick spin. Everything worked as advertised. There was, however, one nice surprise along the way. When I bought my Hoodman RAW-FW8 a few weeks back I was a bit annoyed to discover that I had to turn on my external hard drive (to which the Hoodman was daisy chained) in order to see the unit. After upgrading to Snow Leopard the Hoodman now shows up properly when I insert a CF card without me having to turn on the external hard drive. Small fix, big happiness.
Overall I'm happy with the upgrade. The new O/S has a crisper feel than Leopard and the tweaks and improvements I have tried are great. I expect I will come across more "oh, that's nice" moments as I get to know it better over the next few weeks.
Mac World has complete coverage of Snow Leopard here. And a review from PCMag.com can be found here.
I have to wonder if the Windows folks will have it so good when their new O/S comes out in October. I guess we'll find out soon enough. :)