Compact!
I have large hands. Large enough to palm a basketball, comfortably hold a softball, or open a jar with ease.
Meaning I can comfortably grip large guns, such as the S&W .500, or the Glock 21/20.
I am also 6'4. So i can conceal a full sized weapon, from a highway patrolmen, to a full size 1911, or a full sized M&P or glock.
However. Because I can doesnt mean I do.
I carry compact, 3.4 inch max :-D.
My glock is a 23, My sig is a 229, my M&P is a .45 compact, My beretta is a rare 1984 SB compact.
They carry easier, and feel better in my hand. I'm not one of those guys that needs 17+ rounds to do the job, 10-12 is just fine for me. I dont mind the shorter sight radius. I shoot fine with it.
Also, I dont have to buy as much ammo. I only keep enough carry ammo in stock to do just that. Carry the gun. If i have 3 mags at 12 each, Ill buy 40 rounds per gun. Thus instead of having to buy 60, I buy 20 less and usually save $30 :-D.
Certainly compact for me. But never sub compact, as a guy that wears XXL gloves, they do not fit in my hand and I look like Andre the giant holding a water pistol :-D