I own both an 11-87 and SBE. The 11-87 is a great gun, but I have to keep it clean. I found the biggest problem with the 11-87 is the return spring in the stock getting gummed up with powder, dirt, and seeds, which causes it to slow down and even fail to cycle when it is <10-20 deg F. The Benelli is not as prone to malfunction, but it can happen. I had some problems with my SBE (kind of slow and sometimes didn't fully cycle), sent it back to Benelli and they fixed it by grinding down down the carrier/floor plate. It now works just like new.
I guess if you want absolute reliability get a pump, but even those will misfeed a shell now and then. In fact a friend of mine said his 870 does it on a regular basis and he knows of other folks that have the same thing happen.
To me, the most important thing is the fit. If a gun fits then that is 90% of the issue. With my SBE it fits me like an extension of my arm. The 11-87 is not bad, and the weight forward aspect is good for follow-through, but the SBE just seems to point more naturally. It must be a combination of gun and shooter since I have tried several Berettas and frankly I can't hit anything with them. Unless I really work at getting my cheek down on the stock it isn't pointing correctly. The SBE also seems more reliable and is lighter to carry. The recoil reduction of the gas autos is nice, but to me it really only matters with 3.5" shells. I have never cared for the O/Us since I like the option of 3 and 4 shells. The break open and "instant safe" of the O/U is nice but not worth the price of having a 3rd/4th shot.
I think a good plan is try and shoot as many different guns as possible--most folks at a trap/skeet range will let you go a few rounds with their guns--and find the one that works for you.
An interesting note is that I hunt with 3 other guys on a regular basis. Two of them have bought SBEs after shooting mine. The third guy borrowed one of the other guys' SBE on his last walk of pheasant hunting in SoDak last year. He walked into a weedy return pit on blustery late Dec day and the birds erupted. That was the first triple on pheasants he had ever shot. I figured that the price of pheasant hunting had just gone up for him, but he is cheap and so far has resisted the urge to spend $1500 on a new SBE. His 870 always delivers his limit, but shooting a triple is pretty special.