The Glock 17/26 or 22/27 is pretty tough to beat as a law enforcement combination. The continuity of grip, fire control system, and reloading drill is important - especially in a situation where you have to revert to a BUG. It also makes it easier to qualify with both guns. The ability to use your full size magazines in a sub-compact BUG is priceless . I knew lots of officers who carried full size semi-autos as a duty weapon and a J frame or .380 BUG and not a one carried spare ammo for it. So, would you rather have five shots and your done, or 10 rounds of .40 S&W in your G27 and then reach for that spare 15 round mag on your duty belt? Again, if things have gotten so ugly that you have to revert to your BUG you'll be functioning on gross motor skills. Another bonus is that G27 makes a great off-duty weapon.
If I were still "on the job" I'd still be carrying the G22/G27 combo. I would advise the OP to do the same. Just my opinion, based on 32 years as an LEO.
Since retiring, my primary carry gun is a G23. I do have to admit that I sometimes carry a beautiful little S&W 37 in a Remora IWB in hot weather and stick two speed strips in my back pocket.
Don't get me wrong, I dearly love my J, K, N frame revolvers, but this thread is about duty weapon / BUG combos.