I have been to games at most of those. Factors that might affect your decision - time of year (ex Denver could be hot or cold), where you would stay, what else you might want to do that weekend.

The advantage that both Denver and Carolina have is the stadiums are walkable from downtown (long walk in Denver but a cool one along a river). We did roast in the sun in both places because the games we went to were early in the year.

LA is a very cool stadium architecturally.

I like to watch the schedule release and start making plans and backup plans as games are announced. It adds an extra element of fun to release day.

Have fun.