Just finished a "Trigger Job" on a friends Glock, I use quotations because I don't really consider is a true trigger job. There wasn't much skill required to preform this task though it was a very fun experience as I've never disassembled a Glock before (more then removing the slide). Now have a better understanding of its inner workings and I must say I'm impressed with it. Its not overly complicated and it diverges so greatly from the hammer fired guns I'm so accustomed to working on. I did polish a few of the working surfaces where metal contacts but I doubt it made a great impact on its performance. (I think I would have felt like I didn't actually do anything if I didn't polish SOMETHING!) The job is mostly replacing the few springs that are ingeniously positioned within the pistol!
I have to say, id do 100 Glock trigger jobs before I'd do my CZ 75 or SIG again. Its just that easy.