Ohh, I'm late to the party on this one.
Sorry, guys, I REALLY dislike the Guarneri Quartet set. I got rid of it...and I hardly ever get rid of anything.
Quartetto Italiano is interesting but over-romanticized and soupy in places, especially in the later quartets.
The Emerson Quartet set is a HUGE disappointment. I get tired of all their pausing as if to say, "OK, dumbass, listen up, something important is about to happen."
A set I really like: The Talich Quartet on Calliope. It's out in a budget-priced box, I think. Low-pressure, charming, warm performances, with wonderfully in-tune playing, unlike the vaunted Vegh.
I still haven't heard the Takacs. Gotta do something about that.
Shoot me, but I like the Alban Berg in most of the late quartets. But only in the late quartets.