This is not a camera you should buy without thinking about it carefully. Sigma make good wide angle lenses but they have never made good cameras.
The good thing about this camera, for me, is the Foveon sensor where each light well is capable of registering blue, green or red or all of them (for white). There is no anti-aliasing filter. There is no Bayer filter. Helped by these two things, plus an extremely sharp lens, the photos are extremely sharp from corner to corner (with only about a half stop vignetting in the extreme corners) and the colours, in good light, are vey good and stand out from other types of sensors. The sensor is APS-C size, which is large enough to allow for very detailed images. In the right circumstances, and in the right hands, the photos from this camera can be exceptional.
On the negative side, the camera has a too small rear screen. It is difficult to handle. It has no image stabilisation and it has no viewfinder unless you purchase an extra (and expensive) hot-shoe viewfinder. The cost of this viewfinder (about 150€) should be factored in to the total camera cost because without it the camera is useless for hand-held shots except in good light, due to camera shake. You can shoot raw but not at the same time as shooting jpeg. The viewing screen goes black from time to time. The photo it takes, where there is bright light in the scene somewhere, is sometimes a lot darker than what it was showing you on the screen. In poor light it has trouble focusing. You can manually focus using a wheel but it is useless for judging things to be sharp due to the small rear viewing screen. Colour control is difficult: For brightly lit colour objects it reduces the "pinkness" so you have to set it to a flourescent light setting to correct the colours. You can not choose your own colour temperature. The Sigma cameras in this style are very expensive. It is slow to write away the raw files. Photos not shot at ISO 200 or below are excessively grainy. This camera has 4.65 megapixels and not the claimed 14 megapixels which is not enough for publishing. The lens is only an f4 lens which is a small aperture compared to its competitors.
I don't regret buying it for all the negative things about it, as I have a soft spot for Foveon sensors and wanted one camera with a Foveon sensor that was reasonably priced. I would recommend against any of the much more expensive "Merrill" models with higher pixel counts because they are too expensive for what they are and there are vastly superior cameras of similar style out there like the Fujifilm X100 and Fujifilm X100S with their extremely good low light handling.
So back to the Sigma DP1x. For me, the thing I like about it is that it has the qualities of an old-fashioned Leica in that you can get a decent photo out of a scene that with a normal camera you would not waste time in trying (this works better for indoor shots). It may be just me but see if you get that impression from some of the indoor shots below.