Some good suggestions so far.
I have both gen 3 and gen 4 glocks. I really, really like glocks. They just seem to fit me perfectly. The trigger reset, the low bore axis, the simplicity, durability - all of it.
I had some problems with the gen 4s when I first got them. Those problems have since been ironed out with the new ejector and springs. I prefer my gen 4s to my gen 3s based on grip texture and size. Everything else is the same. I would not hesitate to recommend a new gen 4 to anybody now.
I prefer glocks to M&Ps...but that might change. The big selling point for me was I really like the trigger on the glock and I could never warm up to the M&P trigger. That said, I just bought a shield a few weeks ago, and I love that trigger. It's great. I'm excited to try the next gen of M&P's with the same trigger reset.
Regarding the PPQ, it too is a sweet gun. The trigger is the best of the bunch. I owned one for a while. I shot it many times side by side with my glocks and tried to convince myself it was better, but in the end, the glock was better for me. The PPQ had much more noticeable muzzle rise, while the lower bore axis on the glock just holds it in place and makes doubles and triples a breeze.
Bottom line is that you've got to shoot them all side by side and see which one tickles your fancy. They're all top notch polymer wonders and all will serve you well for as long as you feel like shooting them.
