I'm far from an expert on the subject but I think the SF is merely a slight grip reduction not an overall overhaul of the entire design. I held a G30 SF the other day and it's still the thick brick it has always been except for a subtle but noticable improvment in the grip (to my hands anyway). If you trust the original designs I see no reason to doubt the SF and if it fits you better then all the more reason to go for it in my opinion. Glock is not exactly famous for making sudden moves and radical untested changes like some manufacturers we could mention. So given what they actually did to the platform and their track record for sticking with what works I would rate it a pretty safe bet.

+1 Tuefelhunden

SF= Short Frame

Actually it is not a smaller frame - Glock shaved the grip front to back at the top of the grip to allow for better trigger access. Not much mind you. Same mag capacity. Still a thick brick. Other than that it's just a good old Glock.

From what I've read you have to buy SF magazines and cannot use standard G20 mags in the SF but the SF mags will work in the G20. That'll cost ya.