The Beretta 92fs (M-9) replaced the venerable 1911 as the standard U.S. military sidearm. The 1911 was designed in the year 1911. The 92 was designed in the 1980's. The 1911 is a single action only gun (you have to have the hammer cocked in order to fire it). The 92fs is a Double Action(DA) design, in that it can either be fired with the hammer down by pulling through the long heavy trigger pull for the first shot (similar to a DA revolver) and on subsequent shots or by pulling back the hammer first, fires single action with a short light trigger pull like the 1911.
The Beretta has a decocker so that you can safely lower the hammer back to DA mode when you want to stop firing or after chambering a round. The 92fs model incorporates a manual safety into the decocker which keeps the pistol from firing until it's moved to the fire position (and automatically drops the hammer safely to the DA position upon chambering a round if the safety is in the safe position). They also have "G" models with no safety and a decocker only, and a "D" model which is double action only with no decocker or safety. The "D" model most closely works like a double action only revolver (pulling the trigger cocks and releases the hammer to fire).
With a 1911, you simply leave the hammer to the rear and engage the manual thumb safety. 1911's are best carried in this mode, which is called "cocked and locked".
Also, the Beretta has a barrel with a unique locking block where the barrel stays level as it unlocks. The 1911 has a tilting barrel (Browning) design where the barrel tilts down as it ejects a spent casing and feeds a fresh round. Both types are reliable.
The Beretta has a lightweight aluminum frame and open slide, which helps keep the weight down for such a large pistol. The 1911 is most commonly found with a steel frame, but polymer and aluminum (EMP) framed versions are available. Short of Glocks, the 1911 is the most ubiquitous self defense handgun in the world. It's offered in more sizes, weights, calibers and configurations than any other handgun in existence. They run from a few hundred dollars to over 5,000 for a high end custom gun. There are more parts, modifications and accessories for the 1911 than any other.
I generally consider the 1911 a "professional's gun", as it's manual of arms is complex and you should know as much as possible about the design and how it operates to keep it functioning well. Most modern 1911's are over-engineered for accuracy and speed, forsaking reliability. Some of the most reliable will be well tuned "mil-spec" guns with loose tolerances. 1911 reliability lives and dies on properly tuned extractors and high quality magazines.
A Beretta, Glock, Xd or M&P will pretty much function without meticulous maintenance and custom tuning. The Glocks, Xd's and M&P's are the simplest in terms of function. The trigger pull is always the same and they're easy to disassemble and reassemble for maintenance.
Hope this helps.
