I am a Glock fan whose motto is "Holes on target speak volumes." 16 years ago, after starting out with 1911/Sig 226, I migrated to Glock 17/22 because I got faster match stage times with comparable double taps and shot groups. Mind you, I was very proficient with the Sig 226. At first, I didn't want to accept the facts as I really liked my Sig 226, but stage times and holes on targets are objective and true reflection of what I may do in real-life shooting situations.
One of the range masters who taught PD/SD/SWAT told me to go with the weapon I can shoot fastest and accurately because that extra edge MAY save my life. With tears in my eyes, I switched and never looked back.
It is only understandable to support and rally for "your favorite" gun, but the OP asked "YOUR EXPERIENCE with the S&W M&P". I followed the development of the M&P pistols with great interest because it was claimed as an improvement over the Glock that addressed issues many people had with Glocks (Grip, grip angle, need to shift grip to press mag release, no ambi controls, no frame safety, etc.). I didn't wanted to buy the initial models as I wanted to hear from other shooters what their "first hand" reviews were.
When S&W seemed to have addressed the initial production issues, I bought M&P 40 with the understanding the trigger pull/reset needed to be addressed (7 lb vs 4.5 lb for Glock). Perhaps S&W aimed to appease the DA revolver crowd with the heavier trigger and M&P Pro did address the trigger pull with the 4.5 lb trigger. After my
trigger job that lightened the pull to about 4.5 lbs, I put it through the paces. I liked the pistol so much that I bought another one in 45ACP.
Remember, "Holes on target speak volumes?"
Shooting at 7-15 yards is comparable to G22 but at 15-25 yards, M&P 40/45 really shines. They consistently produce the fastest and smallest shot groups/double taps offhand compared to other semi-autos I have shot over the years (Berettas, H&Ks, Sigs, CZs, Glocks, Rugers, etc.). I think most negative posts stem from side-by-side comparisons with the factory trigger and for most of match shooters, trigger is one of first things that get improved/changed. If you argue the "out of the box" comparison, I will agree that M&P will suffer in comparison due to the heavier 7 lb trigger with longer/mushy trigger reset.
I still like the G17/G22 as G22/G27 is our SD/HD pistols but the M&P45 now earned the nightstand pistol duty. For those who are interested in the M&P pistols, I would highly recommend you examine the features one-by-one and handle/range test first hand with the understanding a trigger job/APEX sear replacement will change the pistol like day and night. If you can, shoot a M&P pistol that has the APEX trigger.
If you like a particular pistol/model for whatever reason, buy it. I know many shooters who have safe full of guns they only shoot at ranges but use a different gun for SD/HD because they shoot much faster offhand drawn from the holster.
Remember, holes on target speak volumes and you should keep the weapons you can shoot fastest and most accurately, just in case.