The goal was to find a durable, reliable and accurate 9mm. In that, the military succeeded. While I (on active duty then as now) would have preferred the SIG 226, I have no major issues with the M9 (other than the slide-mounted safety system).
By the way, MattW, Beretta has never made "junk pistols."
Here's a good synopsis that's been kicking around the gun forums for a long time (I would attribute it, but I don't even know the original source, but it's been verified as reasonably accurate):
The Beretta Model 92FS is the Italian gunmaker's flagship pistol. In the early 1970s, Carlo Beretta, Giuseppe Mazzetti, and the prolific Vittorio Valle began work on a successor to the Model 951 pistol. The Model 92, as it was dubbed in 1976, corrected many of the perceived faults of its forerunner. Foremost were the 951's awkward cross bolt safety and limited 8 round magazine capacity. The Model 92 also introduced a double-action trigger mechanism and an alloy frame. However, it retained the tilting-block locking mechanism and distinctive open-top slide.
The new design quickly gained a 40,000 unit contract from the Brazilian military; however, Italian police agencies wished a redesign of the manual safety. The original 92 had a frame-mounted sear-blocking safety (much like the Colt 1911), and Europeans preferred a firing-pin locking safety and decocker like Walther designs. So later in 1976, the pistol was redesigned to incorporate the desired safety, creating the 92S. Italian police and military orders quickly followed as promised, as did an order from the Indonesian military.
Another boast arrived when the US military's Joint Services Small Arms Program (JSSAP) began a search for a NATO-standard handgun to replace the venerable Colt Model 1911. The lead agency for this program was the US Air Force. While perhaps an odd choice at first glance, the USAF was particularly interested in replacing their hodgepodge of service handguns, which included a large number of .38 Special revolvers. The issue had been forced by the US Congress' refusal to fund acquisition of additional .38 special ammunition.
Beretta made a special version of the 92S (92S-1) for the JSSAP tests which included a repositioned magazine release, an ambidextrous safety, serrated front and back straps, and enlarged sights with white inlaid markings. After a year of testing, the USAF announced that the Beretta had beaten out its competitors and recommended its adoption. The competitors included the Colt SSP, the Star Model 28, the Smith & Wesson 459A, the FN GP35, the FN 'Fast Action' Hi-Power, the FN Double Action Hi-Power, the HK P9S, and the HK VP70.
However, the US Army was still peeved over having the M16 rifle forced on it because of the USAF in the early 1960s. They seized upon the poor performance of the control M1911A1 pistols to suggest that the USAF tests were unscientific and flawed (to be fair, the specific M1911A1 pistols used were at least 35 years old at the time of the test). The US Army went as far to even disagree with the consistency of the mud used in the environmental tests! With the assistance of the General Accounting Office, the US Army was able to convince Congress to prevent procurement.
In 1981, the US Army was given control of the JSSAP pistol trials, and the search began again. 85 requirements were laid down for the winning XM9 pistol; 72 were mandatory while 13 were desirable. Only four pistols were entered this time: the Beretta 92SB (an improved 92S-1), the HK P7M13, the S&W 459A, and the SIG-Sauer P226. However, all four failed, and strangely, the Beretta now finished dead last, even behind the M1911A1.
Congress and the GAO were infuriated by the waste of money with no apparent results. Procurement funds for additional .45 ACP ammunition was withheld until the US Army could formulate a test series that a manufacturer could pass. The XM9 trials started again in January 1984. During the mean time, Beretta had improved the 92SB again, calling the resulting pistol the 92SB-F. The competitors included the Colt SSP, the FN Double Action Hi-Power, the HK P7M13, the SIG-Sauer P226, the S&W 459, the Steyr GB, and the Walther P88. In the end, only the P226 and 92SB-F were considered to have passed all of the tests.
After a series of bids in which SIG-Sauer was the low bidder, Beretta was finally given the contract due to a lower price quoted on its spare parts. Needless to say, SIG-Sauer was extremely annoyed, and there were allegations that Beretta was shown SIG-Sauer's final bid in order to under-cut it. Moreover, the other manufacturers were upset for a variety of reasons. Several had worked up bids before they were told that they were in fact not eligible. Moreover, S&W's pistols had failed due to a mathematical error while converting to English units from Metric in determining firing pin energy.
After a series of GAO and Congressional investigations, another series of tests similar to the XM9 trials were ordered for 1987. However, these started off with controversy as well. The US Army fought to keep the 92F (now the M9) from being retested since it had passed the XM9 trials. SIG-Sauer insisted that the P226 didn't need to retested either since it had passed XM9 as well. On the other hand, S&W noted that the Beretta M9s were no longer being built to the standards of the XM9 trials, having received relaxation of several requirements including accuracy.
Around the same time, reports of M9 slide separations were becoming rampant in both the US Navy and Army. The Navy SEALs were arguably abusing their pistols by firing over-pressure ammunition in suppressed examples, while the Army's separations were blamed on the use of recycled slides from a French contract which contained tellurium. Events were becoming so bad that a Safety-of-Use message recommended that slides be replaced after 3000 rounds had been fired; however, this recommendation was lowered to 1,000 rounds after a M9 suffered a slide separation with less than 3,000 rounds fired.
Beretta took a two-pronged response. First, they sued the Department of the Navy because the SEAL Teams had leaked info of the slide separations to Ruger. Second, they designed a hammer pin with an over-sized head to fit into a groove machined in the slide. Thus, if the slide separated, it would not strike the user in the face. Commercially, these pistols are known as the 92FS
The XM10 tests were finally rescheduled for 1988 after being canceled the year before for lack of participation. Beretta refused to submit samples, so the US Army used off-the-shelf M9s. Beretta protested this, but since they had already refused samples, this protest was rejected. SIG-Sauer also refused to submit samples, standing on principle that they had passed XM9 the first time. S&W submitted their 459 again, and Ruger submitted their new P85.
Again, there were allegations of impropriety. The Army refused to relax their requirement for a chrome-lined bore, even if the barrel was made from stainless steel. Moreover, the S&W failed tests that they had passed in XM9. They were the only pistols to pass the XM9 accuracy requirements, yet they failed the XM10. The S&W also failed the corrosion tests in spite of the fact that the affected parts which failed XM10 were made from stainless steel, while the same parts in the successful XM9 samples were made from carbon steel. Ruger wasn't provided any reasons as to why their samples failed.
However, in spite of the military controversy the Beretta 92F has an excellent reputation in US law enforcement agencies, including the Los Angeles PD (the largest vocal exception is the NYPD's Emergency Service Unit). No slide separations have been reported, and the only part known for excessive wear has been the locking block. This was recently redesigned with radiused corners to prevent breakage. The 92FS has a stellar reputation for accuracy and reliability, and as long as the user has large enough hands it is an excellent choice in a 9x19mm pistol.
It is a done deal as the military is now acquiring different pistols to replace the Beretta. 
