The M9 is a solid tool. I think there are better pistol options out there for more individualized roles but we will never see that in today's Military.
Lots of folks have shot lots of rounds though them and love them.
I've been on the side of the house where I've fixed the broken parts in them.
I can't say I would ever purchase a new one. If one came up that was the right price for something, I may indulge and buy it.
I don't think they are a bad sidearm for what the military has needed them for.
Yes, much of the problems have come from the checkmate magazines. It does not matter how great of a firearm you have, if your magazines are garbage that weapon is worthless.
I've just seen enough problems with them at various round counts, particularly in the higher ones that I don't feel the need to run out and buy one. The are great pistols for a lot of people. I've even shot battalion high scores with them. They are great and easy to shoot pistols.
As far as the Ranger friend? Well how many WW2 vets or Korean War Vets that carried and used the 1911 chose that one when they were done with their military service? It was familiar.
Once again I'm not going on a M9 rampage on either side. Several of my friends in the service have a civilian model in one form or another. I even have a close variant to a Army pistol, a Sig P229. The M9 is a perfectly serviceable pistol. And its easy to fix when it breaks. Ive fixed a few hundred or so I would guess.
Its like anything else out there, if you know the limitations and the parts that can or will go bad you are okay.
Cock them if you've got them and lets all just banter about as we engage targets down range.