Does anyone have this washer? Yes.

While waiting for more specific responses to your other question, you could check out this long running thread here on the Miele W-1 line of washers: https://www.gardenweb.com/discussions/5434365/miele-w1-t1-washer-dreyr#n=1093. You also may find detailed discussions by searching the threads at the washer "enthusiast" site AutomaticWasher. Searching on "WXR860" there will get you very specific threads, searching on Miele W-1" will get you more responses, generally.

As for fitting king-size comforters, AFAIK all of the Miele W-1 washers available in North America, including the WXR860, have the same size drum. The question about fitting comforters in them is discussed in several threads here including the very long running one linked above. (Just open the thread and do a word search on "comforter" to find the specific posts there.) If that's a TL;DR issue for you, the short answer is that king size down comforters and duvets reportedly will fit and come clean in the Miele W-1 washers; down comforters collapse when wet. Thick and heavy king size comforters and quilts stuffed with thick- noncompressible wool, batting or such won't fit.