I've owned a number of Glocks, but except for the 36, none of them felt good in my hands. (I have small hands.) The M&P line feels much better (with the small back strap) and the Shield feels the best of all the M&P line. Otherwise, the polymer that fits and feels best to me is the SD9VE. Of course, no pistol feels as good as a 1911! I haven't really tried a Gen4 Glock, though.
Here lately, I've read a lot about Glock problems...brass to face, and no real combination of recoil spring, ejector, and extractor that seems to work consistently in all guns. Seems like the "Glock perfection" isn't quite the same anymore. I know that any maker can put out a lemon, but seems like Glock is going through a difficult spell.
One thing about Glocks...you can find parts and aftermarket accessories galore for them. Much more so than any other pistol, except maybe a 1911. I wish they worked for me, but they just don't. I sure would like to have one of the Gen4 "Made in USA" models, but I'm not sure of their current reliability.