Issues with highlight recovery - they clip the highlights very easily indeed - and the false colour in-fill between backlit tree branches with the Quattros have compelled me to revert to using the Merrills, which suffer from neither of these issues.
It is all very, very disappointing.
With the new VF attachment the quattro is sexy. But... as you said (and many other said) the Quattro is not up to the Merrill quality, even if some peps try to prove the contrary by wasting hours in PP and denoisers and sharpener or whatever. I do not count the funny denial propaganda of some illuminati over DPr...
Sigma should listen really hard around this part. If the upcoming DP3Q and SDQ produce such grainy noise at base ISO (which is freaking ugly, disappointing and gruesome) this experience will be a total fail (it is already a fail), period.
Sigma won a lot of passionate photographers among the years with the DP line, the pinnacle was and still is the Merrill series. Now they lose clients, lost their international evangelists and, above all, lost credibility by a large margin (because yes, a lot of Merrill users are professionals or even MF users and when they see a poop on the floor... they know by fact it is a poop on the floor).
