The only thing I can see to criticize about the P30 is its priciness, and perhaps the mag release for those who fear James Bond will get the drop on them and leave them with only one point-blank shot center of mass. And unless one is actually on the Teams or in LEO, the standard V3 trigger pull is far more likely to spare one an embarrassing trip to the ER in a real life draw situation than to hamper one's style. Plenty of time to make that long first trigger pull while acquiring the sight picture....while Ed noted
Seeing some comments about the scarcity of H&K P30 magazines, I searched on the phrase "H&K P30 magazines". The first item yielded was:http://www.hkparts.net/extendedwebgobbledegookredactedI have written before that the reason I am carrying an M&P at this point is because I walked into a gun show some years back with the intention of buying the first good Glock 19 or full-size M&P 9 I found for four bills or less. I found one of each, but the Glock was beat to hell and had those wretched XS Big Dots* and only came with one mag, while the M&P was LNIB with two. Yeah, I planned on replacing the sights anyway, but until I did, I'd rather deal with the conventional 3-dots on the M&P than the short bus sights on the G-lock.
The thing about the Glock and M&P is that, not only are they perfectly serviceable pistols, but they are practically ubiquitous. The only ones in the industry that come close to that level of aftermarket support (other than the 1911, which could rate a separate post, actually) are the XD, which I cordially dislike for reasons which largely no longer apply, but let's just say our relationship is... tainted, and the P-series SIGs.
Although the days of internet delivery do lessen dependence on the stocking proclivities of the local gun shop, there's still travel. If I'm anywhere from Rochester, IN to the high plains of Colorado, the local gun store is likely to have accessories, mags, holsters, and whatnot for the Glock or M&P**. Not necessarily a big deal, but it's reassuring.
Of somewhat more relevance is the fact that, for any new type of accessory, it's the Glock and then M&P kids who usually get served first. The others get it later, if at all. I think that Crimson Trace's Lasergrip is handier than a pocket on a shirt, but if you want one for your P30, well, tough bananas.
But this is stuff that's important to me, and might not be all that important to you. I think the P30 is a better pistol than the M&P 9 in nearly any quantifiable way, but not enough to offset certain intangibles I care about. I think if you want to rock... well, whatever it is you want to rock, then get down with your bad self. The only person who has to be comfortable with my shopping choices is myself.
*Not to rehash the whole XS thing but, the usual argument is that, yeah, it might be slower and harder to use well on small or distant targets, but it's Really Fast! on close, wide open ones. So, you mean that in situations where I really need my sights, they're harder to use, but in situations where a coarse muzzle index is really all I need, I've got these sights on my gun because something or other? Ooookay.
** Of course, this is a generalization. Right now, for instance, all the M&P 9 full size mags on the market have apparently fallen into a black hole. Good thing I had, like, nine or ten already...