Hi Gilles,
I have a Sinar m camera system, and I really love it. It is extremely flexible due to its modular design built around its focal plane shutter (1/2000 maximum). It can be configured as a stand alone 645 camera which can take four special AF Zeiss lenses (40, 80, 120, 180) as well as all the Hasselblad Zeiss C/CF/CFi/CFE/F/FE lenses with focus confirmation. The autofocus mechanism is extremely fast and accurate. It also has a Nikon lens module that accepts all the Nikon F lenses as well as the Zeiss ZF lenses, but without autofocus capability. And, of course, it can be used with a Sinar P3 view camera as well. In addition, it has interchangeable viewfinders for either waist-level or 90-degree prism.
Basically, if you love Zeiss glass, you will love this camera. Zeiss makes four special AF lenses, three of which are improved autofocus versions of the following Hasselblad V lenses: 40mm CFE IF, 120mm CFE, and 180mm CFE. The fourth AF lens is an 80mm / F2.8, which is a completely new and improved lens design from Zeiss, with the latest improvements in flare reduction, contrast enhancement, and of course now the autofocus. And, all lenses are sharp wide open.
The only disadvantage for some people is that the flash sync is not very high, only 1/100, and you cannot make use of the leaf shutters in the Hassy lenses. To me, it is not a big deal, since if I need higher flash sync, I switch to a Hy6 or even a Hasselblad V camera. The advantages of the Sinar m are in so many other areas as mentioned above, plus its ability to do 16-shot images with the 54H back with "true" MLU.
I will try to post some images, to help you see what the camera looks like.