I'm currently running an 'ancient' mid-2007 MBP (2.4 GHz & 6 GB of RAM) on Snow Leopard quite happily. I ran Lion for a while, but due to a few pieces of legacy s/w that didn't run on Lion I went back to Snow Leopard.
At some stage I'm going to have to update my s/w, but I'd like to see how long I can keep the old MBP chugging along. As a photographer I use image browsers, occasional Photoshop and occasional video editing.
So I'd appreciate hearing comments from anyone who may have a similar machine to mine and what their experience with general performance/speed has been with either Lion or Mountain Lion. Thanks very much.