I should have prefaced that my audition of the LCD2 vs LCD3 was rather limited. I've had the LCD2 on loan for more extended periods in the past, but the comparison with the LCD3 was done in a meet setting.
The immediate impression when I put on the LCD3 was that it felt more "shouty". I tried this several times with different songs and I could tell within seconds. The upper midrange felt pronounced and sharp compared to the LCD2, like the vocals were forcing their way into my ear (an exaggeration of course). This tonal difference was strong enough to distract me from much else. I'll give that the bass felt better on the LCD3, but the seal and comfort (I really like the LCD3 pads) was much better as well so I figure that was part of the attribute.
Edited by Armaegis - 3/27/13 at 8:37pm