Overall I've been very happy, though I just sold my base model 15" rMPB and am awaiting the haswell version when I'll buy a new one.
The image retention can be a real thing and I did have it very badly on my laptop. I brought it in to an apple store, they look at it, agreed it was bad, sent if off and I got a new screen with no issues.
Having a dGPU was a pro and a con to be honest. It wasn't really powerful enough to do games smoothly on anything but low-med settings at non-native resolutions (I emphasize smoothly because I don't count "opening without crashing" the same thing as a quality gaming experience). The dGPU also turns on for seemingly no reason for apps that don't really need it causing poor battery life.
Battery life in general wasn't as good as claimed in my use cases, which is of the main reasons I chose to sell it and wait for the new one.
With those negatives out of the way, everything else about the laptop is phenomenally good. The screen, the build quality, the trackpad (head and shoulders about any other laptop maker), the keyboard, etc, it's all just fantastic.
