I owned a ppq, and I own a Glock and M&P 9.
I think the PPQ has the best of everything in a handgun.
I said this before:
The Big Four in my opinion:
Glock 17 - 2009 and earlier is a legendary gun.. 2013 and newer are supposed to be good to go too.
PPQ - Still kind of rare. Best trigger out of the four. I'm waiting for the 5inch model.
P30 - Many people consider this to be the best 9mm produced today. It costs more and mags are pricey. This does scare people away. My Glock and former PPQ have better triggers than the P30 LEM.
M&P9 - More utilitarian than a glock. People who put themselves into harms way for a living choose this gun to defend themselves. Although not exclusive to this gun, it does speak volumes. I'm also fascinated by reading m4carbine.net where many people would gladly spend $2500 on their personal AR15 but have trouble spending more than the cost of an M&P9 for their CCW.
PPQ vs M&P9 vs Glock vs P30; It is like picking out a shovel at Walmart. Ultimately, they are all designed to make holes and they all succeed at that task.