I think
this was the only decent review of ML.
Well, you have to take Gizmodo with a grain of salt these days. They've got an axe to grind with Apple over that stolen iPhone a while back...
Still wonder if I get an answer for my question.
As far as upgrading from SL... I don't see the problem. Can's speak from experience but were I you, I'd simply clone my mac to an external drive and upgrade either copy just for peace of mind. (And if you have no backup method in place you're on borrowed time anyway in my opinion).