Keep in mind that the LCD-3s are much pickier than the 2s. But get the amping/source right and the LCD-3s pull out ahead by a good margin, at least IME.
Hi Amos, As mentioned above, the LCD-3s need a good desktop amp that's up to the task. But I was very much surprised just how good the LCD-Xs sounded out of my FiiO Kilamanjaro portable amp.
I can't recall the models, but the main rig I listened to these on cost around $10,000, and while I am the last to say money trumps all, this was probably a well matched setup. For me, tonal character is very important and I just plain liked the LCD-2's balance better. It's been too long ago, so unfortunately I can't recall the exact details, but the main impression was that the LCD-3 was more "sterile" (I hate trying to convert audio impressions into words).
When I try out the LCD-XC after my dealer gets them in, maybe I will also do a quick comparo to the LCD-2 and LCD-3 but since those are both open I wouldn't consider purchasing them.