I have owned and carried both as a police officer.
Current departmental issue, starting Monday, is a Glock 23 4th generation.
I currently carry a glock 19 3rd generation.
I work 12 hour plus shifts and I do not have back problems.
I carried a Springfield TRP then went to a Kimber Tactial Custom II. (Aluminum Frame).
Loved the guns, but they were too much weight, for me.
Try running, walking and just wearing all the gear.
It gets heavy. Plus, I have double the round count and half the weight.
Also, I can shoot the glock 19, with either hand, unsupported, and hit my target.
Less recoil, more rounds on target.