The MBP 2012 has a CPU speed of 2.6ghz with turbo to 3.6, the current iMac has a CPU with 3.1ghz and turbo to 3.8. So if I am using an app like Compressor, which uses all cores, I don't think I will see a huge performance difference between MBP and iMac. Since both will be pushing the CPU to turbo and the clock difference is only .2ghz. Or am I wrong in my calculations. Why ask? Well I'm fed up waiting for the iMac refresh and the MBP is whole lot easier to upgrade with SSD and data-doubler in the optical. This giving me something pretty close to an iMac. I do have a 23"ACD as well.