DxOmark (Click here) tested the Sony NEX-5R sensor and it will not be a surprise for anyone here that it got the same score as the previous NEX-5n cameras (78 vs 77 points). So the real question is, will you spend hundreds of dollars/euro more to buy the NEX-5R? The answer seems to be no! Currently the NEX-5n is the most sold camera at Amazon US (ranking here),
Interesting is also the note they added when comparing the NEX-5R with the Olympus E-M5. basically the performance is the same. The real difference and reason why the NEX scores better is that it has ISO 100!