I think the best thing that is coming out of all the reviews (Car & Driver, Autoweek, Autoblog, Automobile, etc.) is that this vehicle is more than just a one trick pony. Clearly, it offers incredible off-the-line performance, but the handling and braking are going to be strong aspects too. The fact that it can do this with a fairly good ride quality in basic modes (and also be relatively quiet thanks to the acoustic glass and active noise cancellation that limits the droning, not to mention the resonator that muffles some supercharger whine), will make it a good competitor for the luxury makers like the X5 M, GLE 63, Range Rover Sport SVR, and Porsche Cayenne Turbo S. I have driven all of those vehicles (and the regular SRT Jeep), and really think I made the right decision going with the TrackHawk. Sure, the interior is not as grandiose, but it is good enough to compete, especially with teh Signature Leather package. The HellCat motor will not have the lag of the turbos of the X5, GLE, and Cayenne, and the power to weight ratio is notably better than the RRS SVR (which is a pretty heavy vehicle). I also didn't love the seats in the SVR or its infotainment system (though the optional Meridian audio system rocks!). X5 M is very impressive, but the enormously wide tires are more prone to hydroplaning and transmitting more impact harshness and noise into the cabin. Plus, even though "German" horses are stronger (since BMW, Porsche, Mercedes, and Audi are notorious for under-rating their engine outputs), there is no way any of those vehicles comes close to 707hp.
