Well, after some longer term evaluation, I can report that the LCD-3 headphones are indeed a very fine product. Count me a supporter of the planar magnetic technology for headphone listening. They sound very much like listening to a set of high end speakers. The tonal balance is excellent, with no noticeable over emphasis on any one aspect of frequency response. They remind me a lot of listening to Stax SR-007 electrostatic headphones. While the Stax phones have a bit more transparency, the dynamics and overall tonal balance with the LCD-3 is more pleasing for extended listening sessions. Hard to beat that.
Although they are pretty heavy, they are none the less comfortable for extended listening. The clamping force on the head is such that combined with the very plush leather pads makes for a comfortable fit.
The phones do require a high quality playback setup to get the best the phones can offer. I'm using a Oppo Sonica SDAC with a Mjolnir Audio Dynalo headphone amp. This combo provides a clean and detailed signal to drive the headphones, and is a excellent combination.
At some point, may try a couple of oter headphone amps for comparison, but so far, the Dynalo amp is a great match for the LCD-3.