Because they just work.
Reliable
Smooth edges...no cut fingers in gun courses, during practice, or wearing through of shirts
High capacity
Low cost magazines (not so much now)
Easy to maintain
Easy to work on
Low cost parts
Light yet handles recoil
Trigger job costs as much as a 3.5# connector and some smoothing with a dremel
Only needs night sights out of the box
Durable
Midsize guns have almost the perfect balance between height, width, capacity, full grip and concealment
Pretty much everyone above has mentioned all of the great qualities of the glock pistols. For me it was because of reliability and accuracy. That's why I enjoy collecting and shooting them.
I bought mine on the recommendation of one of my best friends who is a Glock armorer for his PD. His duty carry is a 21sf and his BUG is a 36. So I wound up with a 2nd gen 17 that I shoot in IDPA. He detail stripped my 17, declared it GTG, and after 250-300 rounds of my handloads I adjusted to all the reasons I had avoided a Glock for nearly 30 years. Mine has a slick trigger job which is one of the main things that kept me away from a glock in the past. The one thing I really like is the availability of aftermarket parts like barrels, slides, triggers and mag releases. I really hate the barrel rifling though, it leads up badly with my favorite cast lead bullets.
Last edited by Ronbo; 09-22-2010 at 09:51 AM.