Well I actually got one for a bit over 2 weeks now. And here are my thoughts on it.
Value for money, the Retina display version is better than the non-Retina MBP 15", and significantly better than the Razer Blade in almost anyway

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Vicey pointed out that by default everything on your screen appears to be the same size as it was on the old MBP with the 1440x900 screen, only 4 times the pixel density, which does make things appear sharper. BUT certain apps, anad more importantly, basically every webpage isn't yet optimised to run at the higher resolution and you get blurry text and images. I'll post screenshots in a second as proof. However you can overcome this problem by simply increasing the scaling so it's at 2880x1800, however this means everything is 1/4 of its original size, so some people may find it hard to read text.
The GPU, GT650M it's decent (better than the GT555M on a certain 'true gaming laptop'), but running things at 2880x1800 is quite taxing, especially when it only has 1GB GDDR5, would have been better if Apple made it 2GB imho. The MBP also offers GPU switching between the Intel HD4000 and the GT650M to save battery life, however the HD4000 isn't great, and with only 512MB of RAM, it can actually cause the system to crash, but if I disable graphics switching (force the GT650M on) or plug the MBP into a 1080P monitor, that problem is gone.
Random crashes with Google Chrome, not sure about you, but Google Chrome is my favourite browser and judging from forums all the new Ivy Bridge MacBooks, Airs and Pros seem to crash at random. I have experienced this btw.