I'm still on my "Arrandale" MacBook Pro (2010), still on Snow Leopard. Mountain Lion would run fine, but I ran into a nasty audio stuttering bug, pretty annoying. Mavericks is still early in its lifecycle, amidst ****** graphics.Yes. Still using Snow Leopard because as I need to run some PPC applications. I will gladly upgrade to latest OS X if I could buy Rosetta for Maverick.
Actually earlier this year I bough a new "Ivy Bridge" MacBook Pro 2012 (MD102LL/A) that I had to exchanged with a friend for a older "Sandy Bridge" Late 2011 (MC724LL/A), just to install Snow Leopard on it.
Perhaps I just need to learn how to install Snow leopard in a VM and get over it . This way I will run Maverick as my main OS and Snow Leopard inside a VM.
The only thing that work on SL with iCloud is Notes under Mail. The rest I prefer having them synced via iTunes...Loved it and STILL using with on my MacBook and MBA. My father has ML on pro and he is not too happy about it, wished he could install Snow Leopard but........ To me it is flawless and have NEVER had any issues with it since if came out ......??? I really wish is had iCloud though as my iPhone, iClould and SL dose not communicate very well. Still I manage somehow. My Safari is 5.1.10 and again zero problem with sites, streaming, whatever. So I feel no need to upgrade.