I own both and really like them both. The Summit is all luxury, looks, equipment and function. The SRT is both, it has every piece of luxury equipment that the Summit has except the rear seat heaters, but can act like a luxury car or an animal. The summit rides better on the highway and at cruising speed it actually adjusts ride height for optimal aerodynamics. Pretty cool feature. SRT has a MUCH better audio system. Love the Saddle leather look in the summit, but love the SRT seats more. The 5.7 is a PIG by comparison to the 6.4. The wife's previous car (2011 Larado x) was 2WD and the 5.7 gave it some balls, but in the 4WD Summit it is a slug. The Summit has a 6-speed which is better for the highway vs the 5-speed of the SRT. The Summit has a metric shit ton of chrome if you like that, door handles, mirrors, trim.... vs body color of the SRT which is much better IMO. One thing that bothers me about the Summit is that fender flares and rockers are the same moulded plastic crap that is on the Larado that I fear will fade in the sun. Should have been body color IMO. The ones on the SRT are different/more aggressive design and body color. Lots of differences in the motor, brakes and suspension.
It boils down to this, what are you looking for? Performance or luxury or both and what are you willing to pay. The SRT has both but you will pay more. The Summit is Luxury only but cost less. I did the SRT because I wanted both, the wife went for the Summit because she could care less about going fast.