Some of the issues I saw with the M9 was with the magazines, but not all. Out of the 15 or so Berettas that I had contact with the most had issues with the extractor or the locking block/locking block pin that is under the barrel. One of my friend's M9s would fire 3 rounds then stovepipe the fourth one. He could clear it and it would do the same thing over and over, wierd.
The wind is always blowing over there, so when the sand storms kicked up , sand and dust gets into everything. The M9s would start choking up a bit, but so did some other weapons too.
My team made a gun run to Balad/LSA Anaconda once. I had to go by armorer's shop to pick up some parts and ran into the privately contracting gunsmith. I asked him which weapons he had the most trouble out of, he told me that the M9s were on top.
Not trying to bad mouthing the Beretta. I had an Italian Beretta once , and it shot great. In my experience , the berettas that we were issued were not up to the task.
I heard that there was a program for soldier to supply their own sidearms. I didn't hear about this program til after I had returned. Turned out that my unit's armorer didn't want the extra hassle. Our EOD asset got to carry their personal weapons. I read that a popular gun rag writer carried his Remington Rand 1911 over in Iraq. It was something about signing the pistol in with your unit armorer, he puts it in the books as if it was part of the arsenal, then the armorer signs it out to you , just like any other firearm.