The other critical issue IMHO is the power transfer at different frequencies. Very few amps stay totally flat with inductive loads across the frequency spectrum. The worst offenders are SE (single-ended) which can deliver a lot more oomph at some frequencies than others, usually getting flabby in the bass. On paper, their frequency spectrum looks great, but the results when listening reveal important frequency response interactions with different cans. Or another example, 'stats where the impedence decreases with frequency, the power delivery can be quite different at high frequencies than at low frequencies. I'm not talking just the ability to deliver frequencies, but the ability to deliver them with equal emphasis.
I guess this is one reason why bench testing by reading specs can be so misleading about the actual sound. When the amp has to really slog into its power supply to deliver the goods, that's when you discover the real players versus the also-rans. My old electronics teacher used to explain that an amplifier was just a way to modulate the power supply, so the design of the power supply is at least as important as the amp topology, and choice of active devices.
Back on Topic:
Anyway, thanks to everyone who has contributed to this topic! I'm on the list for the LCD-2's also, so I'm interested in hearing owners who can share their amp/can experiences.
Between now and when my name is called, I'm trying to decide whether the LCD-2's are just FOTM, or whether there's a better choice. Also whether my current amp will be a good fit. For us tube guys, putting transformers in the delivery chain can improve the linearity of the power delivery, so I'm modestly optimistic that the Audez'e will work with my amp. If not, all these experiences are really relevant for thinking about the ideal HPA topology for the Audez'e LCD-2's.
At the moment, I'm auditioning stuff. I'm fairly happy with a pair of loaner T1's using my own Mapletree Audio Ear+ HD Super, with the high-output impedence jack. Trying to decide whether to keep the T1's or wait for the Audez'e. It's a lot of money, but at least I can re-sell if it doesn't work out. Fortunately, the output of my MAD amp is pretty robust into the low impedence jack, so it won't be a power issue, but may very well be a power transfer/delivery issue. Glad to hear at least one person say they liked some things about the earlier MAD Ear+ HD amp with the LCD-2's.