I don't think anyone thinks that. I just read a little piece in Car Craft this morning about a Charger running 9.47 @ 153 with a super charged 6.1 and this car still had a full interior and was street legal. The Challenger Drag Pak car is going to be over 1000 lbs lighter, with the same engine it will be in the 8's.
The original post implied you could go to your local Ford dealer an buy a Cobra Jet Mustang and take it to the track and run 8 seconds. The car is delivered with a 475 HP motor so that is hardly the case.
As moper stated and I tried to state it's only when these cars are running in the same class to the same rules will you be able to make any real comparisons as to the perfromance. I believe they will be comparable.
As for appearance I like all three of the new pony cars and would be very happy to own anyone of them. But there are things about the appearance of all three I don't like and just from a pure asthetics standpoint the Mustang would get my vote. If I were to consider one of these cars to buy it would have to be as a year round daily driver and I could not justify the GT, the SRT8 or the SS for that application. The Camaro with the 300HP v6 and 6 spd manual that gets 30 mpg would get my nod.