You've had some good advice here. I own both 11-87s and a couple of M1S90s. Unless you are going after big birds with the gun, I'd skip the SBE.
I shoot clay birds informally with some friends, maybe a 100 rds/afternoon, and sporting clays a few times a year. Unless you are recoil sensitive, I don't think you'll notice that much difference between the Benelli and 11-87 with target loads. The difference is more obvious with magnum loads. If you are a league shooter, shooting many 1000s of rounds a year, a gas gun might be better.
If you can, shoulder the guns and see which fits you better. The Benellis should come with stock shims, so you can adjust for a better fit. I am partial to the Benelli for most bird shooting, except for turkey hunting. I usually hunt with an SP-10, but if my back hill seems steeper than normal, I'll take out my 11-87. I also have an 11-87 set up for slug shooting.
The Benelli action and chrome lined barrels make cleaning a snap. The Benellis are also extremely fast cycling. I like to try my Tom Knapp imitation every once in a while, tossing 5 clay birds up in the air and (attempting!) to bust them before they hit the ground. Usually, the ground wins. Yeah, I know he can do this w/8 birds...
You will like the Benelli!