Re: Glock 17L or 34...
Do you want a combat/ccw handgun?
Or do you prefer a holstered sidearm camore suited to matches?
only you can decide
For me i own (2) glock 23s, same size as the 19.
I use handguns as sidearms, companions to a rifle usually.
If your handgun serves as a primary/only weapon, then the longer barrel makes a bit more sense.