As a firearms instructor who helps train people to use firearms as dedicated defensive weapons, I usually have the most push-back from folks who are "trigger pull" snobs, regardless of the type of their favored handgun.
It's usually easier to help shooters who don't think that they've already found the penultimate handgun, and who aren't prepared to quickly denigrate every other handgun at the slightest opportunity.
Of course, it's almost always easier to work with semi-auto pistol shooters who learned their foundation skills on DA revolvers, as they usually find anything to be easier and "better" than a long & heavy DA revolver trigger pull.
Besides, once you ramp up some minimal range-induced stress, and throw in some unexpected (and previously unpracticed) demanding courses-of-fire and drills, the typical "trigger pull snob" usually discovers that their finely tuned, custom trigger isn't nearly as helpful (or as practical) as they liked to envision while standing around on a static range, leisurely shooting slow-fire targets. Or while sharing stories at the gun shop display counter.
I own, carry & shoot Glocks and M&P's (and a lot more brands/types, but those are the two mentioned in the OP).
I've been through the Glock and M&P pistol armorer classes enough times to sometimes forget how many times it's been for each of them. (Without going to find and count certificates, it's either 4/3 or 4/4 of each.)
I could list many perceived features that could be debated as advantages and disadvantages for both, but
both are fine, decently reliable, good quality examples of the modern plastic service-pistol trend.
I'm presently carrying a new production issued M&P40 (as a reserve after my retirement), but that's because they
gave it to me. I'm old enough, and have been doing this long enough, that I'm no longer interested in carrying anything of
my own as a duty weapon. If they'd given me a Glock, I'd be carrying one of those for duty use.
As far as I'm concerned anymore, let it be
their gun that gets subjected to the rigors (abuse) of police work, meaning taken into evidence or subjected to unexpected damage, loss or theft during normal use.

They'll give me another one that looks just like it.
I'll continue to carry my own Glocks and M&P's as retirement CCW's, though. I'm much less likely to need to use one of them as I go about my normal life. Besides, I like to carry smaller guns as retirement CCW than the full-size guns in either the Glock of S&W M&P lines.
Brief and brutally honest? Really? It's just a plastic service-type pistol, when all is said and done.