I just ran a calibration check on my X7 which already had the screen compensation applied.
Colour accuracy was fairly good out of the box. I will try and post some screenshots later. Greyscale as expected tracked with colour temperature too high, although absolutely consistent across the range, and about a dE of 7 from D65. Default gamma was pretty much spot-on 2.2!
I easily got the greyscale under control, requiring as usual, the biggest drop in blue and then green not far behind.
However, I cannot get anywhere with the CMS at all so far. Although the colours are not that far out, the adjustments for hue and saturation seem to have little or no effect from either end of the ranges. Luminance I found a bit more change with. The other REALLY annoying thing, is the screen blanks between each change of value, so calibrating will be a SLOW job.
Anyway, I never had any issue calibrating my HD950, but perhaps I am doing something completely wrong here. I had a look at the new axis control to see if it would help, but the dE was actually lowest in its default position to start with for the colours I was trying.