personally i have no idea as i have not heard any of these speakers in mature systems.
considering only current production models.......
@Elliot G. just did a set-up with the M7 with subs. he obviously knows the Gobels; both the Nobelesse with and without subs and the Majestic with and without subs, and Harley's room where they did the Nobelesse review had Wilson XVX's i think with subs that he heard prior to the setup of the Gobel's. so that's 4 in highly tuned rooms (not sure the M7 set-up/room is in that category?) he has heard. not just in show set-ups.
Elliot? i know you are the Gobel distributor, but any comments?
those are a few of the players around and under $500k..
there are other large box dynamic speakers like those to consider such as the new Vivid Audio Moya M1. the big Tidal LA, the big Zellaton, and others.