http://www.dxomark.com/Lenses/Compare/Si...92_175_792
This compares it with the Nikkor 24-70 f2.8 and the 24-120 on the D800 (so as to use a similar sensor)
In pure resolution terms it looks like it's better than the 24-120 and in the same league as the 24-70 at similar apertures (a touch worse at 70, a touch better in most of the field at 24). Of course the latter lens is faster, and has much less native distortion!
Look forward to Klaus' results!
The interesting question to me is could a much better lens have been made for FF with the same size and weight? I would have been willing to pay (even!) more if it could -- if not too much more.
But maybe the answer is no: it's pretty small and light for a FF 24-70. If the answer is no, the next question is (and each of use will answer this differently) would we have preferred a heavier larger better f4 24-70?
My own answer to that is no; when not constrained by weight I'll use primes. This lens is for bushwalking...and as a system I'm getting results that are on the whole more satisfying with it than the OMD and Panny 12-35 I was using before at not much more overall weight and bulk. Plus, when I'm not bushwalking, getting amazing results.