Pros: Remarkable performance on another level altogether, both measurably and audibly..
Cons: Heavy headphones and cable, needs a powerful, fast amp and top source for best results and there's a 2-month waiting list.
While they are usable out of even an iPod, as well as the lowly amps I have tested, out of high-end gear they give a remarkable presentation that eclipses that of just about any other headphone, both measurably and subjectively.
While the HD-800s were supposed to be the ultimate headphone and do measure incredibly well, sonically it always seems that, to get the most musical enjoyment out of them requires extra work or compromise, whether it be a re-cable, a slightly warm-of-neutral amp or whatever.
If there are compromises with the LCD-2s, then they are in the weight, somewhat tight initial clamping and initially stiff pads. If these things, ultimately don't turn out to be a problem, then the rewards are great.
The entire sound spectrum, from the bass through to the treble is both fast and even. However, there are no large peaks in the frequency response unlike so many other headphones. They don't require tonal trickery to make the music sound good. That means that one can easily get the impression that they are darker sounding. However, whereas with, say, Grados, the music jumps out because of the treble or bass, with the LCD-2s, turn the volume up a bit and the music just jumps out as it is. Vocalists suddenly appear in front of you and instruments come from their precise locations with beautiful timbre and accuracy whether it be percussion, brass or wood.
Overall, they make headphone listening wonderfully enjoyable sonically, if preferably in a reclining chair or sofa to take some of the weight off your neck, but importantly without trickery, just purity.
Asr put it succinctly in one of his posts thus: