I won't allow that the Benelli is one bit "better". It is newer, it is different, and it is ooooooh aaahhhhh I-talian (moment of reverence), but that means squat to me. I will come completely clean - that is a negative to me. It is very interesting that when they came to design a top of the line tactical shotgun, Benelli did NOT utilize the world's finest, cleanest burning, most reliable, miraculous, fastest, Tom Knapp endorsed, yada, yada, "Inertia" driven action. Nope, they went to a gas operated action. A lot more like the 1100 then revolutionaryly different. Amazin'.
The basic 46 year old 1100 action has been adapted to every shotgun use known to man. I do not dispute that the M4 is a better tactical shotgun; I do not know, but I believe it to be the case. In as much as it was designed for that end I would sure as hell hope it has an edge on a standard field/target gun with a few add ons.
It's like the old 870 versus Winchester Model 12 argument. I have owned and shot a Model 12. I have a friend who collects them and sits in the duck blind and lovingly caresses them. I much prefer a Wingmaster. It works every bit as good, I like the feel and balance better, it is as or more reliable from everything I have seen in 61 years, and it costs a lot less money to make and buy. I do not care that some craftsman did not have to sit and file and polish individual parts to get that 870 to tick properly. Neither pump is a fine English double and no amount of handwork will make them one. If a part does break on an 870, 99.9% of the time it's a 5 minute parts swap fix. More often than not with a Model 12 it's time to go see the gunsmith. That does not spell 'better' to me.
If you think something is better, you are absolutely entitled to your opinion, but let's not stir opinions and facts too much please.