I have the ASI1600MM-Cool. I know you asked about the MC, but I think most people went for the MM. I preordered it in April, and have only just recently been able to use it. I am quite impressed with it. Despite the couple small shortcomings, such as a bit of amp glow (which calibrates out perfectly if you disable any kind of dark optimization or scaling) and early on some driver issues (most of which seem to be dealt with), it is a wonderfully versatile camera. It's good for pretty much anything...planetary, lunar/solar, DSO with either long exposures or short, lucky imaging, etc. It cools quite deeply, -40C vs. ambient is a no brainer. I think it is a great camera, considering the cost it is an excellent camera.
I recently started testing with high gain, short exposure narrow band imaging, and the results so far are quite impressive:

The above is a mere 1h45m of total integration. Only 13.5m for Ha, 37.5m for OIII and 54m for SII. I'd like to see any other camera on the market do that with a similar FoV. ;) It can sustain around 15-17fps in 8-bit mode when using short exposures as well, which is good for lunar imaging:

The biggest difficulty I have had with the camera was getting it, and my Atik EFW2 filter wheel, adapted to my Canon lenses. I use lenses most of the time for imaging, and the weight of both the FW and camera have been a bit too much for most EF adapters. I have only been able to use one particular adapter due to the limited 44mm backfocus requirement. I've managed to make it work, but it is not ideal. If you go for the MC, then the weight of a filter wheel would be a non-issue.
Outside of that, no other real issues. With the MC, you should be able to make some very high resolution, high detail images with very short exposures.