Mac OS X 10.6 Reviewed by Ars Technica

The only Mac OS X 10.6 review that we need to read. Everything else is secondary.

http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.ars

Highligts:

1. Developer oriented release (though there are new end-user features)
2. Intel-Only
3. Around 50% in disk footprint
4. On demand driver download
5. Chinese input using touchpad
6. No Rosetta by default (by installed on demand from the net)
7. No Quick Time Player 7.0 by default (but can still be installed)
8. 64-bit kernel (but not the default)
9. 64-bit system applications
10. OpenCL
11. Grand Central Dispatch (GCD) facilitates developing multi-threading applications using lightweight queues served by centrally controlled threads
12. LLVM / Clang tool chain in addition to GCC
13. Block construct (i.e. closure in many dynamic) for C language
14. Quick Time X
15. Only US$29 for existing Leopard users
16. Exchange support via Mail, iCal and Address Book
17. Screen recording
18. Faster boot / shutdown time

Play attention to the compatibility. There are massive overhaul under the hood (it is said that 95% modules touched for refinement)

http://snowleopard.wikidot.com/start

It blocked me from upgrade as my wife is using Adobe CS3 (which has known issues with 10.6)