Best wishes on your new gig!
Of the M&P, as others noted, it's highly ergonomic, and is considered "duty/defensive-grade" by all, much in the same manner as the Glock.
As a competitor to the Glock, it has perhaps just a touch less aftermarket support, but that should not impact you in any way, as all of the duty-type accessories - such as sights, lights, and holster support - are well catered-to, and you won't find the lack of support typical of Springfield's striker-fired double-stackers to be an issue.
I would not worry if the Shield doesn't fit your anatomy,
@Keystone19250. The M&P double-stackers are full-size frames (the compacts are obviously abbreviated with respect to grip length), and that usually implies a different dynamic where it comes to the hand-to-grip interface. The ambidextrous slide-stop/release is something that most shooters find to be a bonus, for single-hand manipulations.
I am less familiar with the current generation of these weapons - the first generation really benefitted from the help of the Apex Tactical trigger enhancements. Given that this is your duty weapon, I am not sure what will/will-not be allowed, but I believe that the current generation's trigger is appreciably better than the former's.
Prior to the influx of the modern single-stacker 9s and the increasing popularity of the Sig and H&K striker-fired pistols, I used to see a lot of other students with M&Ps in training classes, and they were just as reliable and durable as any other autopistol on the firing line.
I know that magazines aren't cheap and that you're coming off a job-change, but given your line of work, I would recommend that you procure at least two more magazines as soon as you can. It'll be nice to have the additional spares (on-body or not) just in case of breakage, but what's more is that having the spares will allow you to really train (since it reads that you're going to be issued an ammo allowance from your employer), without the worry of magazine damage. Once your financial situation settles down, I'd recommend investing in at least yet another pair of mags - if not outright getting another five more (for a total of 10), so that you can dedicate one set of five for training use, while the other set of five gets set aside for duty use only (to minimize the chances that they are damaged during training/practice), after they have been properly vetted.
