I decided to update my macbook air 11″ with 2gb of ram to OS X 10.8 mountain lion. So far the impression is, that it is faster in speed than 10.7 lion. I have not made any use of the new features like notifications. Which is supposed to intergrate social media into Mountain lion. I found all software I use could run on Mountain lion. I did have to update a few of these to a later version, but that was just some time, it took for this to happen via the App store.