Bill, I would tend to steer you towarss either the M1S90 or the M3. You really have to decide if you want the M3 to have pump action as an option. If so, what option would that be? Would you ever really use/need the pump? You'll have to answer that one.
There's a reasonable amount of accessories for the M1, which is what I personally own. To date, after owning it for over 2 years I have never wanted or needed the pump option. The M1S90 is one very serious shotgun. Absolute blinding speed of cycling and it has been flawless in operation for me.
People generally only get the M3 if they plan to use "goofy" loads in the gun like very light loads, flares, rubber pellets - loads that will not successfully operate in the semi-auto M1. So, it's up to you.
If you do get it, I would recommend putting a Pachmeyr Decellerator recoil pad on the stock. The Benelli's are very light and therefore have quite anice kick. The addition of the pad allows me to shoot 200+ rounds per day with no "after-effects".
Good luck deciding.
CMOS