The M&P 9's are incredible designs and values in the semi-auto pistol class. I'm an H&K zealot and am painfully accustomed to paying well over $600 for their excellent handguns. But I just purchased an M&P 9 and it is a shockingly well made, great shooting and great feeling machine. I was actually astonished how well balanced and how nice a 'machine' it is. It really is something that is more than the sum of its parts. To be fair, I need more experience with it but for now it gets my vote.
All that said I have yet to try out a Walther (PPQ M2). I have a sense that they are the hidden gem(s) in the industry that, for civilian levels of need, give up little to nothing to H&K for a quality handgun. Both German engineered and built, now both are making striker-fired pistols. I'd be very interested in a one on one comparison of a PPQ and a P30 but the Walther is not commonly stocked out west here.
B