I thinks the rMBP would be a nice choose for me.. but.. with the rMBP I am a bit concerned about lags and IR. Should I be? Or are these problems all fixed with the latest rMBP models and ML. Or...If I choose for the rMBP, will it be better to wait for the next update this summer? I'm not in a hurry at this moment. Maybe a bit impatient...
cMBP or rMBP... that's the question..
edit: Some typo..
I wouldn't be that concerned about lag. I don't notice in on my 13" rMBP and I came from an 11.6" Core i7 Air.
That is not to say there is no lag at all. However, you are unlikely to notice any coming from a 2007 MBP. People tend to notice it most if they came from 2011 or 2012 15" MBPs, which were silky smooth. The rMBP has 4 times the pixels to push, and it has taken Apple a few updates to Safari and the graphics drivers to work out some issues, but it appears to be software rather than hardware, and the software is being sorted out. After all, we have had screens of this level of resolution for a long time, just not in a 13" or 15" notebook.
As for image retention, some people have it and others don't. It seems to be an issue for earlier LG screens. I don't notice in on mine, but I've had mine only about a month. I'd say get one and if it develops an issue have Apple look at it.
After owning a rMBP I can't see myself going back to a non-Retina screen.