People can debate durability, but I've seen more broken M9 locking blocks in my career than is appropriate for any issue duty weapon.
I would imagine you could say that for any gun that is used at the scale the M9 is. How may are in service 250,000 +/-?
Probably closer to 500,000 than 250,000. (I think the original order, back in the mid-1980s, was 450,000 -- and they've bought more, since then.)
This whole discussion may be another example of the much-discussed INTERNET FACT/MYTH conundrum at work -- and the problem may be more apparent than real.
The US Military DID have problems with locking block failures,and with slides cracking. Retrofits and modifications seemed to resolve the problems. Beretta supposedly designed the locking block to survive 22,000 rounds, and I've read tests of Berettas pushed to near that number of rounds without problems.
That there have been any failures of any sort is a little surprising, as sidearms really aren't used all that much in combat, and non-combatants generally use them only for periodic qualification courses. (Handguns are a poor source of stopping power on the battlefield... one Navy Seal I met said he'd rather carry an extra full canteen than a pistol, happily relying on his other weapons instead of a handgun.)
All that said, and if the stories we hear are TRUE
and not internet myths, can you cite
any OTHER major gun maker's product with comparable problems? The US military and Federal agencies use a lot of SIGs (but NOT almost 500,000), and there have been MANY, MANY 1911s in service over the years.
(Note: I think a lot of folks are still P.O.d that the U.S. mlitary chose an Italian-made weapon rather than something from Colt, S&W, or Ruger, and will happily repeat stories that make Beretta look bad.)