Just got back from RMAF. I hesitate to give detailed / definitive impressions given the fact that it was meet conditions (and there was a lot of background noise in the room), but I will say the following...
-I found them really comfortable (the earpads feel absolutely amazing) and noticeably more luxuriant on the head than the LCD-2, BUT for those who have a big problem with the weight and clamping, I don't think the LCD-3 is going to be of much help. I also really liked the angled cable at the front - it feels like it's tugging less and isn't in the way as much.
-If you're looking for sufficiently different from the SR-009 to justify a supplemental purchase, then you won't be disappointed. They sound very, very different from the SR-009. The Stax is incredibly neutral, airy and transparent; the LCD-3 sounds like the LCD-2 - thick, lush and musical, with the best bass I've ever heard on a headphone. Going from the Stax to the SR-009 was a huge change - I traded breathtaking transparency for the realization that there is an incredible amount of low-end information and richness that the Stax can't quite convey.
-I didn't get a chance to A/B the LCD-3 with the LCD-2 while I was there, so I unfortunately don't have a strong opinion about whether it's worth a $1,000 upgrade. They certainly share a house sound, and there is a little more refinement apparent in the LCD-3 sound, but I can't give more definitive impressions than that without hearing them side by side in a quieter place.