Hi all, I have a 2009 4,1 Mac Pro and am thinking of upgrading it to either a rMBP 15" (highest model) or the new 5K iMac, but I'm not sure which one I should get. I have a 27" Viewsonic monitor and would connect the MBP to that vs. using the screen. I don't really need the portability, but it is nice to have it in a small, transportable package if I move. I mainly use the machine for music apps (Logic X, Pro Tools) and photography (Lightroom, Photoshop). One nice thing with the iMac is it takes 32GB of RAM (which is helpful for large sample libraries). However, there are some concerns around the new iMac's GPU with a 5K screen and I wonder if it will be overkill. Any suggestions would be appreciated. Thanks!