Compare Mountain Lion to Snow Leopard on older MacBook Pro?

Has anyone installed Mountain Lion on a MacBookPro (version 4,1) 17 inch, 6 gigs of RAM, Core 2 Duo Processor, 2.5 GHz) Can you give me some idea of it's speed compared to Snow Leopard? (Will be upgrading from SL)Any information you see as important beyond the standard Apple disclaimers-advice would be appreciated?

It's tempting because It runs impressively on my MacBook Air 2010..same processor but it's an Air.

Thanks