I used to give preference to Southwest for cross-country (US) flights, partly because of availability on particular routes, but over other direct flights because of the boarding experience. For $15-20 (not sure what it is now) I could pay for the automated check-in and be near-guaranteed a seat in the A group that was better, for cheaper, than trying to get an equivalent seat at an airline where they were picked ahead of time.
That makes sense if you prefer to be close to the front/exit for quick deplaning.
I tend to just relax during both boarding/de-boarding since it's only a few minutes difference anyway and the effort/stress of trying to move quickly outweighs the few minutes savings. If the seat is pre-selected, I can simply wait for the line to go away and board last without standing for 10m. It seems to me that most people rush to board first even with pre-selected seating (perhaps optimizing for space in the overhead bins)
If you have a connecting flight with a short layover, is the exception where I want to be right near the exit. So I guess it's more of a preference thing
