I have a buddy that floats all around the world from craphole to craphole, most of the time all they carry are Sigs. And yes, LEO usually has glocks
I heard good and bad about both to fair about it, both run equally well when clean, with decent ammo. As for the levers and what not on the Sig, just any pc of equipment, you learn it and get used to it.
The Glock (.40) in that pic I have run crap ammo through it. In the course of 2 magazines I had 8 or 9 FTF and a couple of stovepipes. They aren't "wonder pistols" as some would believe, they do have limitations.
My other Sig a 229SCT, I've run very dirty with 3 or 4 different types of ammo, maybe a 300 plus round session, no issues. That doesn't mean I couldn't make it fail in some way. I've never had any crap 9mm ammo to test the theory.