I wouldn't kick either out of bed, but I give the edge to sample 1.
I place comps like this in audacity, mute one pair and then hit solo on the same pair (turn solo on/off to instantly flip back and forth). Then give a full listen through and pick out a quiet section to listen for microdetail. There seems to be something in the upper presence band on the guitar in sample 1 that I just thought was a better image. Not necessarily more prominant, but a better focus. I caught it 3 or 4 times when flipping but it wasn't consistant. The microdetail didn't tip it either way. Dunno, like I said, I wouldn't kick either out of bed, but if I were the one schlepping the gear, I'd probably skip the ad2k as I'm not getting enough difference to lug all that stuff around.
edit: listening gear: macbook > optical > usbpre2 > audeze lcd-2 rev2