I've had both vegan and leather LCD-2.2s, and the vegan is much more comfortable. I'm not sure if it's density of the foam, or just the texture's better breatheability that makes me think that, though.
I'd suggest trying it with the yoke rod things extended as far as feasible. Neither the -3 or the -2 is as comfortable as the HD800. Not even close. The Audezes are more durable and sturdy than the HD800, but the Sennheiser wins in ergonomics. The only problem I had with the 800 was that the giant cups pushed a bit on my jaw... but that was easy to adjust.