The Z also weighs less and has a shorter wheelbase. I'm guessing that translates to a better driving feel that is hard may not come across when using numbers. That's probably just a personal preference though; like wanting the rumble of a V8.
Impressive times for the Z. I wasn't aware that it was actually that fast. However, if you're going by Motor Trend numbers, the current Mustang GT is about a half second quicker in the quarter mile. And on several different occassions, C&D has demonstrated that the Mustang GT is quicker than either the regular Z or Nismo version around a road course.
Certainly things like feel and looks are far more subjective. I can certainly appreciate someone preferring the looks and drive of a Z over any of the other performance coupes between say, $28k and $35k. I may have been one of them if not for the ludicrous price of the Z.