I'll speak for the 1911 fags

(being one myself)
For me, the reason I used to hate Glocks is they're just boring. I like guns that have history, and a level of mechanical coolness. Glocks have neither IMHO. Another reason why I didn't like Glocks is because everybody loves them. No shit. If something is uber-popular I probably hate it.
But, mostly it was the trigger and plastic. Once you're used to a good 1911 trigger, everything else sucks. It's a fact. So, I hated the Glock trigger.
Then, there's the fact that they're plastic. Hate plastic guns. Still do, but I make an exception for Glocks.
After buying one, and shooting one, I found that they're very good guns. Performance is good, aim is good, trigger is better than most other non-1911's (still not a 1911 though) and reliability is insanely good.
So, if you're not a 1911 snob like me, or tend to like "tacticool" type guns, you will LOVE a Glock. Even if you are a 1911 snob, you have to give Glocks their due. They are exceptionally good hand guns and I would trust my life carrying one. (I still prefer 3 pounds of 1911 on my hip though).
/edit/ I'm probably going to get another 27 to replace the one I foolishly traded away. Or better yet, a 30 (being a 45 ACP fag also)