If it is duty carry I would go with the longer barrel for the slight difference in velocity and the slightly better sight radius. If I were to be in a defensive position against an armed individual and could OC without issue I would want every advantage I could get.
Like they said above, BUT if your firearm is rated to use it, +p or +p+ will get you more velocity, 100-150fps over a standard load using +p and maybe tack another 50-75 on top of that for +p+.
YMMV depending on type of ammo and how they load it out.
You will likely not see a significant difference in performance with a 3.8" vs 4" barrel in 9mm. Typically, you don't start to see significant differences until you get below 3.5". The farther below 3.5" the more difference you're likely to see. See note on barrel implications on page below: