Back in September I purchased the Snow Leopard install DVD to use it's Drive Setup app to perform more reliable SATA hard drive partitioning on my '07 Mac Pro, before I re-installed Tiger, from the machine's OEM install DVD.
Over the weekend, I installed Snow Leopard on my external FireWire drive, connected to my Mac Pro. I used the migration tools to get all of my apps and settings onto my new installation of Snow Leopard. I ran the OS updates. The latest update appears to be Mac OS 10.6.2. Everything seems to be as stable as in Tiger 10.4.11. Rosetta runs my MS Word X app and my Retrospect Client 5.0.540 just fine in Snow Leopard.
The only problem I have with Snow Leopard is the default gamma setting of it's software display driver, when running my two Graphite 17" Apple Studio Displays. It is so bright, my CRT displays' manual Brightness and Contrast controls cannot bring the display into a controllable range for calibration. Even when I use System Preferences to set the Gamma from 2.2 to 1.8 and the Color Temperature to 6500. This may be my only obstacle to moving up to Snow Leopard, from Tiger, for now. I guess Apple's LCD Cinema Displays don't have the manual Brightness and Contrast control limitations that my CRTs have.
Photoshop CS4 seems to open and display image files a little faster under Snow Leopard. InDesign CS3 is stable in this OS. If I were to permanently upgrade to Snow Leopard, I would clean install the OS and manually re-install my Adobe Apps instead of using Apple's migration tools. A permament migration to Snow Leopard may require my investment in newer display technology.