MH:
I have owned carbines (also competed with) in both 14.5" and midlength 16". Loved them both. When it came time to thin the herd, the wonderfully accurate 14.5" Wilson bbl'ed carbine was sold. It's Wilson barrel thought it was a match barrel. It was a fantastic shooter, even at 500m (not yards) Connaught Ranges.
Now I'm down to a single AR for competition purposes and it's the keeper. Longer gas tube, better gas feeding, gentler cycling process... life is good.
I do have to say that I quite liked the 14.5" stepped barrel since it looked very cool!
Now I like my 16" mid-length since it appears to be an abbreviated 20" rifle barrel with decently looking proportions.
Enjoy the addiction. Let us know what you select!
Barney