The AF is much faster under QK mode under 1.07.
Under 1.07, although under QK mode the screen still freezes, it is barely noticeable. This is because AF is achieved quickly under 1.07. So the screen freeze does not really affect composition anymore.
Under 1.06 and 1.05, the AF was slow and went hunting. During the "hunting phase", the screen is frozen which was very irritating and prevented proper composition.
Alternatively, under 1.07 you can choose FR-focus instead of QK-focus. Using FR-focus, there will be no screen freeze at all, but the AF will be the same old speed as 1.06, just that you can see the AF hunting phase entirely and compose without any freezing.
You do realise that the discussion above is all within the space of milliseconds to a second.
IMHO, as I am primarily a street photographer, I feel the GXR is just okay for street candids in good light. In most other situations, I still prefer GRDIII for street candids or children photography, because the snap function is more forgiving on GRDIII than on GXR. For portraits, macros and still subject photography, the GXR is clearly superior in every respect.