[Beanie-Bean]

Saw a Glock 21SF Gen 3 that I like. Reading online, I see a lot of people say they like them but also a lot of people say it's the "worst Glock made". How is it?

I have both the Gen3 and Gen4 models, and the Gen4 is probably one of their best models, hands-down.

I also read about "KaBoom" issues with them. Should I be worried about that?

Only if you're shooting reloads, and you have a squib or double-charge...

What kind of longevity can I expect out of one?

The Gen3 I'm using as a nightstand pistol was an LE trade-in, and was produced in 1996. I have a Glock 23 which is even older, and I still have and shoot it, too.

Hope that helps.