It's interesting that the HD621 will be able to be updated to handle 3D via firmware. I asked that question to three different M employees over the past 9 months with all of them saying it couldn't and would have to be new hardware to accomplish it. Hope it is true.

My gear: Trinnov CI, 271, 8000.1(SEs), 7200.1 HC (SE), 320s, 3200s, Seaton F18 subs, MS200 (2nd zone), 218, 210.
Other: JVC RS-4100 projector, Lumagen Pro Radiance, Panamorph DCR anamorphic lens, Stewart G4 130 screen, Kaleidescape Strato K, Rvolution 4K player and Zapitti NAS, Oppo BDP-203,Roon Nucleus