I like a full sized service pistol. I chose the Glock 20 because it gives me flexibility. I fire 10mm and with a quick barrel change, 40 S&W. I could also get conversion barrels for 357 SIG and 9x25. These all feed well from the 10mm magazines. I do not think I have large hands and I do not find the grip too large. Maybe it is an issue if you have small hands.
My carry gun is a Glock 27. It is exactly the same size of the 26. I also have the 9mm conversion barrel and 9mm magazines which gives me more options.
All in all, all the Glocks are good choices (except for that 380 ACP version, maybe). I am a late adopter of the Glock. I think it is the first major design since the 1911.