Yes, I have first hand experience with both.
Either of the KK500 stocks have more adjustability and, in my opinion, a better grip than the Anschutz stock. The walther cheekpiece offers 2 different profiles though it is somewhat fiddly to adjust.
The ergonomics of the KK500 action are better than any of the Anschutz actions. This is most apparent in prone where I can load without lifting my elbow off the mat but there is also significantly less movement loading in both kneeling and standing.
The sight extension tube arrangement on the Anschutz 54.30 is well made. I do not like the sight extension tubes from Walther, they are held on with grub screws. There are dimples in the barrel so they go back on accurately enough but I think that is a poor attachment method for something that you take off and on frequently.
The walther buttplate has lots of adjustment capability, the Anschutz not much.
They both produce good barrels, I don't think one has an accuracy advantage over the other.
The Anschutz extended scope rail works on the KK500 so switching from irons to scope is not problematic.
That is all I can think of, hope you find this helpful.