GT500 all the way! The GT500 is a great machine!
Pros: 440 or so rwhp, 420 or so rwtq, Great looks, Prestige, 5.4L Supercharged V8, Love the supercharger sound, easily upgradable (can add 100rwhp with a $1000 budget easily), posts some impressive times at stock.
Cons: Its heavy, nearly two tons (coupe) or is over two tons (convertible), Muscle car handling(due to 57/43 f/r weight ratio, and heavy). Interior looks too similar to the GT interior. If you don't like supercharger whine, you won't like this car.
Conclusion: If you can get over that it is still a muscle car, and does not have the best of handling, you will love this car!