Every model of Glock 
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Why do people buy them? crazy!
Because they're reasonably priced, reliable, and easy to modify if so inclined. I own a grand total of 1 a Glock 19 Gen 4, and once I changed the trigger to a flat face model, its been a good solid (not great) pistol. Will it replace my Wilson Combat Beretta Centurion or CZ PCR? Nope, but it will always have a place in my safe and at the range.