Well I decided to buy the upgrade from 4. I made my decision based on the statements that it was faster than 4 and the use of the radial filter and the additional clone tool. I discovered that my M images won't work in the version of Camera Raw I have so almost all of my editing there is going to be done in LR. I know there are ways to make it work, but I wanted to not go through all of the steps. So far I really haven't seen a difference in speed, but I just started using it. I have slowly made a transition from doing almost all of my processing in CS 5 to LR. I think with the amount of time I use LR compared to Photoshop, I can justify this upgrade. Getting CS6, not so much.