Hi, Quick question, is a 15" top-spec rMBP as powerful as a top-spec 21.5" iMac? Both the latest versions of each model. I ask because they both use a mobile GPU and the same amount/bus speed of RAM (the MBP uses low-voltage memory but research has shown it makes little to no speed difference). The only differentiator is the processor, but there doesn't seem much in it besides the iMac having a desktop-class i7. I'm considering between the two - again - when I upgrade. The MBP won last time, as it was the first to have an i7 and blew the iMac away at the time. I can always use an Apple Thunderbolt Display to get the desktop experience, I just don't want to lose out on the power front. It'd be used for audio recording and post-production, probably dealing with up to 40-50 tracks with software effects (hardware rack gear being better placed in an optimally-tuned studio, in my opinion). I am drawn to the iMac largely because, as I have a room set-up for audio monitoring, it could stay in one place with everything wired up to it. I guess the same could be done with the ATD as well. That said, the occasional portability of the MBP could be useful for live applications.