when I've compared the at853's to the akg 480's head to head (there's a few shows on the archive featuring both mics) the 480's always sounded smoother and more rich (mostly in the low end), but it was NOT that big of a difference. Seriously, as audiophiles we look for those differences, but I wouldn't be suprised if non-audiophiles couldn't tell the difference between the two.
Granted, my reference system is not up to par, and a better playback could better reveal the strengths of the akg's and the weaknesses of the AT's, but at least 50% of my recordings are requested by somebody else who is probably not an audiophile.