Get Sigma dp Quattro at B&H Photo. I am a fan of the Sigma DP Merrill line. As this was written, get 22% off on the Sigma DP Merrill line.
See also the review of the Sigma dp2 Quattro.
Color rendition can be tricky with Sigma sensors. In this series, the Sigma dp0 Quattro color rendition in mid-day sunlight is examined.
In my review of the Sigma Merrill and Quattro cameras:
Sigma dp0 Quattro: Color Rendition in Daylight (Glacier Path)
Includes a tint-variation series to show the color balance characteristics. This article may be useful as a starting point for further evaluation by Sigma dp Quattro shooters.
f5.6 @ 1/1000 sec, ISO 100; 2015-07-25 12:07:22[low-res image for bot]
SIGMA dp0 Quattro + unspecifiedLens @ 21.4mm (14mm)