I would say both. Mainly because they are two different beast for two different purposes. I currently have a GT500 with a Raptor on order. I personally could not be without a 4WD vehicle so I would say the Raptor first if I had to choose. But then definitely the GT500 next.
I must agree! I have both and they really shine in their own ways. I've had the Shelby now for about two years and performed a few mods to bumb the performance level. We changed the gearing to 373, added the L&M 66MM TB, JLT CAI, Jon lund custom tune,diablosport mas mafia,Kenne Bell dual BAP along with the Whipple 2.9 blower with smaller pulley. The car runs great and is a blast to drive! The car is not a dd, we only drive it on nice days or to local car shows. I love the Shelby and could not be happier with the 800hp beast, However, after purchasing the Raptor three weeks ago I've found a new love. I traded a 06 Taco 4x4 TRD offroad for the Raptor and could not believe the difference in ride,comfort and overall quality! The Raptor is practical for everyday driving and gets as many/more looks than the Shelby. My wife drives it to work everyday and loves it (I have a work car),it's really scary the attention she gets!!
If I had to sell one it would be the Shelby, I love the car and there's nothing like roasting the tires in third gear. The Raptor on the other hand is great for all types of weather, it's so comfortable and I love all the luxury add ons. I could not function with out a (now this) truck, seems like I'm always using it for something.....