I've had a pair for around a year now and swap between them and my RS1s.
For me they seem to excell with acoustic instruments ,especially guitar.There is bass present, it goes deep and is quite well controlled, not boomy but it isn't pushed forward in the mix. On some recordings higher pitched vocals sometimes seem a little harsh, but that can also happen with the RS1s and maybe as much the fault of the recording or my gear.
I haven't listened to the W1000s with classical music, right now I'm working my way through the Grateful Dead Golden road Box set and it sounds just fine.
The remastered War of the Worlds set sounded better with the ATs than the Grados. While I find them quite acceptable with 'rock' music that isn't their forte.They have a good seperation around instruments and vocals. There is a write up on the ATs at the 6 Moons audio review site that you might find worthwhile also.
I like them and wouldn't part with them. They're very well made, comfortable and as a good sounding, closed back phone at an affordable price they're hard to beat. It doesn't hurt that they look so good either.