I have a couple of Gen3 G17s, and they work flawlessly. Before using the gun, I'd recommend reading the manual, and then cleaning and lubricating your Glock in accordance with the instructions provided in the manual. Do try several different types/brands of ammo to see what your Glock "likes" best, and I'd recommend staying away from the really cheap imported ammo, at least until the weapon has been used a bit with good quality ammo.
"Placement is power" -- seen in an article by Stephen A. Camp
(RIP, Mr. Camp; you will be remembered, and missed)