2016 R/T 392 Owner here.
>reliability
Only 5000 miles into mine, but no problems so far.
>comfort
The inside is cavernous, and you can fit 3 people comfortably, 4 if you're a short guy.
>build quality
There was a rattle in the headliner I took care of. All I can say if make sure you give it a good test drive and a thorough inspection.
>interior
Interior is much improved after 2015, more padded pieces, less cheap hard plastic.
>practicality
Can fit 5 people if you're desperate and all of their luggage for a week too.
>visibility
Rear pillars are massive, but you just need to position your mirrors properly to make up for it or get the blind spot monitoring.
>ergonomics
My 392 needs 91 octane and an oil change every 6 months.
>infotainment
It's okay, no complaints. 2017 comes with car play/android auto, sub-2017s do not.
>community
Old people who hate millenials and chill guys.
>sound
stock sound system is alpine and suits my needs since I don't blast music. More often than not, I will turn it off and listen to the engine sounds instead.
>how fast they feel from the seat of your pants
Haven't driven any of the other two, but my 392 feels fast but controllable.
>which is least nerve racking in crowded urban areas
they're all probably equal, but the challenger will feel the largest.
>which is most fun a twisty backroad
probably not the challenger, but I doubt the other two fare much better.
>etc etc etc
engine sound is amazing stock
extra note: there isn't much you can do mod wise to increase horsepower, SRT squeezed as much power as they could and you'd spend a few thousand dollars for like 50-100 unless you get a blower.