I have a 21-scat pack (392 T/A) that I drive daily. I also have a 20 Hellcat redeye that sits in the garage most of the time. Here are the differences i see.

The scat pack has a much stiffer ride, the Hellcat in auto mode is much softer ride and is adjustable if you want to change it. (Wife has a 17-scat pack and rides the same as my 21-scat pack)

Hellcat much louder.

Both cars have Brembo brakes, the hellcats are much larger and make way more dust to clean.

The performance, there is no comparing the two, the hellcat seems a bit much to drive every day in my opinion, i put a drag radial on the back of the hellcat, car is less likely to end up in the ditch now.

Both cars are impressive for ride, comfort, fuel mileage etc.

The scat pack doesn't have the blower whine or performance, but still a fun car overall to drive. I get low 20's with the scat commuting about 80 miles a day, the ride home is in rush hour traffic too.

If I'm buying a toy, definitely going with the HC, If daily car id go with the Scatpack.