Really not much difference, if you plan on carrying it, id go for the 23, if not, the 22. My 19 conceals pretty easily, same size as the 23....
Glock 22:
LENGTH
186 mm / 7.32 in.
HEIGHT
138 mm / 5.43 in.
Glock 23:
LENGTH
174 mm / 6.85 in.
HEIGHT
127 mm / 5.00 in.