I just got a DP3M; I don't like the Quattro pix out there, and anyway the european price of 400E was just barely affordable as an impulse purchase. I sold my RX100 to buy this.
After 15 minutes with the thing, my take is that texture rendering is quite exceptional, the lens is really really sharp, I mean ridiculously sharp, did I say sharp? This tiny thing runs rings around my Canon 1Ds3 and 85/1.2. I don't think it is quite in the category of my erstwhile Phamiya P45+, but then it's also a bit cheaper.
Handheld use is ok in real daylight only and the shadows go noisy quite fast, focus is more than fast enough if you are used to MF. I tried ISO 800 indoors and got banding. No luck, this seems to be a low-ISO image-maker.
The remarkable acuity of the sensor translates into environmental color reflections on your subject, even skin becomes a mirror. This is disconcerting. As "Cooter" would say the color is not global.
Oh, and if you need to photograph your nearest and dearest feminine friend and she's over 25, just use a different camera if you value your life and the parts that bestow manhood
I value mine enough not to publish my portrait test - my usual retouching technique failed here.
One item not covered in other reviews - if you get some sort of 52mm tele lenshood (I have an old Nikon screw/clip in) then you can wrap your left hand around the lens and the experience of holding the lens with your left and squeezing the large shutter button with your right index is both stable and comfortable.
The Sigma processing software is precisely as horrible as everybody says. The camera menu system sucks. The camera heats quickly. Build quality is mediocre. There is no in-camera stabilisation. However, did I say the low-ISO images are sharp? I mean really really sharp? And on the sample below you can see both the color of the sky and the deep shadows?
It's amazing what $400 buys you these days. I mean the RX100 is good value for money at current pricing, but this close-out sale last year's model Sigma thing is not a compact, it's a *camera*. Even for us spoilt folks on the MF forum.
I will follow up ...
Attached 100% crop of default-processed file, handheld, late afternoon.