I never shot a compensated pistol, but would think the discharge of flame/vapor out the top might be a huge distraction to the less experienced shooter.
A personal defensive weapon is gonna be used at very close distances so I don't think the compensator model would be necessary.
For OP, I would stick with the mid size Glock, what else comes close for size and weight vs capacity?
I don't own a Glock 9 but have a couple 40's. If I knew for sure I would be in a fire fight I would want a high capacity Glock. Proven reliability + plus highest capacity = best chance at survival. Disregarding shooters marksmanship abilities, probably why the vast majority of LE agencies choose them.
JB.