I'm wondering whether anyone who's used Mountain Lion since release has decided to go back to Lion? My MacBook Pro 13" (Early 2011) really struggled with Mountain Lion. This is even with 8GB RAM. I noticed ML had to work really hard and I never got the battery life after 7 or 8 cycles like I did with Lion. Even doing very light work on web browsing (minus Flash) and using low resourced programs (even on idle, the battery was much warmer than when I had it running on Lion); I had 2 hours slashed off the battery life. When I started to push with Flash and do some basic photo editing, it went further down into 2.5 - 3 hours. I did the same with Lion when it first appeared and it seems to take two or three major updates to sort itself out. My feeling is that ML is optimised for anything that runs on SSD or minimum the 15" models that have extra battery and dedicated video graphics.