Texas Star - a pal from my new agents class killed a guy with 147 Hydra-Shoks from his issue Sig 226, less than a year after we graduated. It was an off duty thing - he got carjacked when he and his wife pulled up in front of his residence. He waited until the bad guy used his gun hand to put the car in reverse then shot him in the upper body from outside the driver's side window. I don't know how many times, but the results were quite fatal. No glass in the way on that one.
The 9mm was our main issue cartridge for a relatively short period of time - from the demise of the 1076 in 1991 until the Glock 22 was adopted around 1999. Prior to that, there were plenty of privately-owned, Bureau-approved 9s, SWAT guys got hi-cap Smiths (from one of which the ill-fated 9mm Silvertip was launched on 4/11/86 in Miami), and HRT had Novak Hi-Powers. I'm sure plenty of shootings happened with them, and I'm unaware of any problems with either the Hydra-Shoks or the 147 Gold Dots that replaced them and remain the current issue 9mm ammo. As you said, its pretty much penetration uber alles in today's Bureau. Expansion is nice to have, and there are pretty stringent accuracy standards, but if that bullet won't make it 12 inches into the jelly, forget it.
Right or wrong, that's what they want. I don't have a problem with it. At least half of our shootings involve shooting into vehicles, and the same ammo is issued to guys in Hawaii and Alaska, so we tend to err on the side of penetration. Personally, I'm happy with ammo that will go through windshields, steering wheels, forearms, leather coats, cell phones, iPods, rear view mirrors, boom boxes, whatever.
I was issued a 226 in 1991, but I got my 220 while I was still in Quantico on my Dad's FFL, and I've carried it ever since, so my only experience with the 9mm was in the Air Force (briefly) and on the range.
Once I was looking for a guy who kidnapped and shot an apartment manager. We started with his last known address, and wound up talking to the victim. It was a couple months after the shooting, and the manager, a young black guy of 28 or so, was back to work but barely getting around. The bad guy was a doper, lived in the complex, and was trying to get the apartment manager's kid brother to sell for him. The manager kicked the guy out, and a week later was abducted at gunpoint for some payback. He made a run for it, and the doper opened up on him with a 9mm. He scored a couple of hits, then the 9mm jammed up. He switched to a .45 and knocked the manager to the ground. He walked up and put a couple more hardball rounds in him and left him for dead.
The guy finished telling this story to us, then said "What kind of gun you carry?" I told him a .45 Sig. He asked the same question to my partner, who carried a 228. He told him "a 9mm". The manager, sitting at his kitchen table in his bathrobe, shook his head and said, "That 9mm just made me run faster, but that .45 knocked me on my ASS." Anecdotal to be sure, but it made me feel pretty good about my choice of blaster.