I am with Keith (?) here. I feel that DSLRs are better at high ISO than MFD and I tend to shoot minimum ISO also my DSLRs. For me, MFDB is on tripod, careful manual focus, minimum ISO, medium aperture, MLU and cable release. Otherwise DSLR. But, I rather use DSLR on tripod, manual focus (LV at 11X), minimum ISO, medium aperture, MLU and self timer/cable release.Under those ideal conditions the MFD system gives sharper images. Better images? That is another discussion, but I obviously think MFD has it merits, else I would not use it.
I'd rate the IQ180 in a totally different league to any of the Canons I've used (7D, 5D II, 5D III, 1D4, 1Dx), even at ISO100.
As an example comparison, the pixel pitch on the IQ180 is pretty close to that of the 1DIV. So for a given focal length, if you need to stop any "action", or compensate for any possible movement or vibration of the camera, you're going to need the same shutter speed on both. I've recently shot with both IQ180 and 1Dx from a helicopter. There is simply no comparison whatsoever between the two. The IQ180 blows the 1Dx out of the water (or I guess, sky, in this case).
Obviously you need good light, but when if it's possible to pull the shot off with the IQ180, I cannot for the life of me understand why anyone - given the choice - would use a DSLR.
"MF and high shutter speeds don't mix well" is not the case in my (admittedly, limited) experience.