I'm going to go with the minority (as far as the poll results anyway) and say that I would prefer the 16 GT.
430-450 (whatever it ends up being with the Coyote upgrades from the Boss engine) is plenty of power for me for what would be a daily driver car (I can't afford two cars right now).
662 HP is unbelievable, but what's the point if the car has trouble getting it to the ground and still has ye old medieval ox cart suspension.
Here's some food for thought on getting a new S550 GT:
-engine upgrades by Ford should make a big difference; their stated goal is to have a new GT beat the 302 on the track. That would be pretty impressive.
-car is sleeker, lower to the ground, and has wider hips, giving it a much more planted feel.
-interior is light years better than the current S197 models, GT500 included
-ye old carriage rear axle is gone and replaced by a multilink unit. No more jarring over bumps, no more unsprung mass issues, better handling.
-front suspension is also all new as well. 2 for the price of one IMO
-new technologies and comfort features that will enhance the driving experience for the average joe who will be using this car in the real world and not on a drag strip
To me, I would gladly sacrifice the horsepower for a better overall package. Obviously looks are subjective, but I think it looks nicer than the current gen.
And for those that truly want a hi-po car, the new GT350 is coming next year, supposedly with a wicked 5.2 NA variant of the Coyote good for around 550 HP. With a better suspension and handling, that car should whip out lap times that are easily in the ballpark of the current GT500, and still be good enough to kick ass on a dragstrip if that's where you want to take it.
Just my opinion.
Current: 2015 Ford Focus SE
Former: 2007 GT, Satin Silver