Keith - took a few shots to compare the SD1m and Quattro H today. Used a DG lens (35mm f/1.4 A) and a DC lens (10-20 mm f/3.5) and the same settings on both cameras. I much prefer the look of the Quattro H images. They are little sharper and much better color - a bit warmer. The SD1m images are quite blue by comparison. The color issue is not such a big deal because it can be fixed in post. But I do like that the color looks more natural coming straight out of the camera.
One thing surprised me that shouldn't have. That is, with the DC lens, the corners are much sharper on the Quattro H compared to the SD1m. The difference is very large. Of course, this happens because the sensor is cropped a bit on the Quattro H with a DC lens. Therefore the corners on the Quattro H are not on the edge of the sensor for a DC lens. So I now see the advantage of using the DC lenses on the Quattro H - keep your DC lenses. I will try the 18-35 f/1.8 DC lens on the Quattro tomorrow. That should yield some nice results.
I prefer using the SD1m - quieter shutter, easier to takes lenses on and off, and some of the settings (such as program mode) are easier to change. But despite that, in my view, the Quattro H is a clearly superior camera - the images are much nicer.