I have a sincere fondness for the 92-series and contrary to other comments, never had corrosion, reliability, or durability issues. The triggers are usually very nice and the unique slide design not only dramatically reduces the chance of ejection failures but also means the gun can have a much lighter recoil spring than its peers in the marketplace. That would ordinarily make it a good choice for people who have less upper body strength, but such people also tend to have smaller hands. The trigger reach on the 92 is very long (can be alleviated somewhat with a factory short trigger) and the grip circumference can be difficult for some people to handle.
Between the Glock and the M&P it's almost more a matter of taste than anything else. Before the gen4-era fiasco, Glock certainly had the edge in terms of reputation for durability. Today, I'd say they're pretty much on par with one another. I'd give the nod to the M&P in terms of slightly better ergonomics -- as long as you don't rely on the right side slide release lever -- and the Glock has a better trigger out of the box. If you spend enough money swapping parts, you can improve either one of them to the point that it should be fine for you.
The M&P also has the 9mm lockup/accuracy issue, which candidly would be the main reason I'd personally steer toward the Glock if forced to choose between the two in 9mm.