Superb colours! They don't look too "digital", unlike my Sony A5100, which is what made me buy a GXR again (had one a couple of years ago). The A5100 is great for certain subjects and looks -- and video, especially -- but for personal photography I think I'd rather have a GXR. Probably the only thing that would have made it better would be a CCD sensor (you get stuck at 800, but then I was shooting a Digilux 2 with max 400 ISO for years before I could finally afford a "real" Leica!).
Maybe it's just my eyes or monitor or combination of both, but Canon LTM lenses seem to work particularly well with the GXR. Apart from Kuuan's, I have also seen memorable samples from Canon 50mm 1.5 LTM. But that 35mm 2.0 is tiny! And I like the SLR-type focusing ring.
My GXR has finally arrived, secondhand but in almost new condition. It has a C Sonnar mated to it right now, and I'll see if it doesn't rain this weekend to go and grab some samples. This thread is one of the best on RFF.