IMHO -
It is hard to beat the H3DII-39 in the price/performance ratio of single shot. All the DSLR features of real-time, focus adjustment throughout the aperture range of HC autofocus lenses, and lens correction with older CF lens via the CF lens adaptor. Compatible with SanDisk ExtremePRO 90mb/s CF cards, and large LCD screen. Field/Location and Studio friendly.
Also uses both Zooms (35-90mm, 50-110mm) and the HTS 1.5 tilt/shift lens adaptor - all from same company. Additionally, if you are not familiar with the recent H3DII-31 pricing, you should contact your Hasselblad reseller for local reference information.
The H4D series (40MP & 50MP) bring the TrueFocus technology to augment the items above. Focus, rotate, shoot - keeps original focus area sharp in the recomposed frame.
The 40MP model utilizes microlenses (like the 31MP) and provides a shifted dynamic range of ISO 100-1600 due to the efficient manner of directing the photons into the pixel wells across the surface of the sensor. I would recommend the 40MP if you are using available light most of the time.
The 50MP model has a dynamic range of ISO 50-800 and will provide the largest original file to exploit downstream, including the multi-shot model (MS). Multi-shot captures four shots, moving the sensor in a square pattern (over, down, over, up) to overcome the color interpretation of single shot (from the bayer pattern covering the sensor.) Detail is enhanced from the contrast in all four shots and is the pinnacle of image quality. This is the choice if image quality is the highest priority.
Everyone is different, and the Hasselblad models address a range of shooting needs - get a demo of your final select(s), it is the only way to know for sure.
John