As expected, The Phoenix and Master 6 power these phones effortlessly. The LCD3's have unsurpassed bass response. The best I have heard for quality, quantity, speed and detail. Definitely reference. They sound to me just like the FR graph shows, solid bass and mids with highs that are just on the south side of neutral with full details etc. I thought these would be perfect for me, because I am a bass head at heart. However, I'd like a little more out of the highs to match the rest of the frequencies. To me it's a little too much bass tilted.
What was worse was the pressure on my ear canals. The ear pads created the greatest air-tight seal around my ears I've have ever experienced. I would actually put the phones on, and have to stick my fingers underneath the pads to break the seal. Even then there was still positive pressure on the ear canals. This coupled with the heavy weight of the phones made me too uncomfortable to listen to for long periods. I had read that one head-fier experienced a bout of tinnitus after repeated, long listening sessions and I definitely could see that. However another head-fier acknowledged the pressure, but for him it was more akin to custom IEM's. I can't stand those either though.
To summarize I'd say that the sound wasn't worth enduring the lack of comfort associated with them. They are beautiful phones though.
It is possible that they could be the holy grail for some, but I would recommend that they be auditioned in a non-commitment type environment first, especially considering the expense.
One more point to add is that from what I have read, they have significant variability in production. It is possible that not all LCD3's create this ear pressure.
I have heard people use "vegan' pads ie not leather but velour to great effects. It certainly would not seal as well and would bring up the treble & open the presentation somewhat. "Drez" could tell you more as he was the one who spoke to me about 'vegan' pads.
Also I have used alot of TWag (but not with lcd2/3) and it has always opened up the treble a small but noticeable amount from my experience.