The cruelly objective folks at DxOMark have tested the Sony RX1, a camera that has inspired Leica-like devotion (e.g., see the reader reviews at Amazon). It turns out not to be that exciting from an objective measurement point of view. The fancy Zeiss lens tests out with similar numbers to a Canon 35/2 lens and it lacks the Canon’s image stabilizer. The Sony’s Zeiss lens does come up with a better overall score but the notes say that is mostly because the Sony sensor is better than the Canon 5D Mark II sensor that was placed behind the Canon lens for the test. How about the sensor? Really great.. just like the same sensor, more or less, that Sony sells Nikon to put into the D600.
So for the price of a Nikon D600 and a good 35mm lens you get the same image quality and seriously compromised picture-taking capabilities compared to a standard DSLR (see the conclusions in the dpreview.com review).
The Sony does seem like kind of a fun toy for people who love the 35mm lens perspective (I’m not one of them) but the test results don’t show it to be magic compared to a modern Nikon body and well-engineered 35mm prime lens (e.g., from Sigma!).