Photo enthusiasts, professional photographers, and the media now have a valuable tool with which to compare the RAW sensor performance of these medium-format cameras with high-end, high-resolution DSLRs. How is it possible to make valid comparisons between cameras with widely disparate sensor sizes? It's possible by reviewing the cameras' rankings for each of the three separate metrics that make up the DxOMark Sensor scale (Color Depth, Dynamic Range, and Low-Light ISO).
For example, if medium-format cameras do not receive top marks on the overall DxOMark Sensor scale because of their inherent Low-Light ISO limitations, DxO Labs has found these models' Color Depth and Dynamic Range performance to be very striking when compared to high-end DSLRs. Also, despite the clear challenge from DSLRs across all DxOMark sensor metrics, medium-format cameras still lead the way for large-print photography because of their very high resolution performance capability.
(From the press release.)
A sample comparison:
This sample would indicate that there is virtually no difference between the sensor quality of these two cameras, apart from low-light capability (which is not a limitation for the Hasselblad's target market, since studio photographers use artificial lighting. Might be important for you, though). Of course the big difference is image size (39 MP vs. 12 MP). Interesting, as I would have thought that the medium-format camera would have had better dynamic range than it does. I thought that was the tradeoff with high-ISO capability. Guess not....
ADDENDUM: Read Michael Reichmann's thoughts on these new numbers. Michael's actually used a lot of medium-format digital cameras, and, like him, I tend to trust eyes over measurements.