When the 11-87s came out,early ones had problems with the trigger groups, occassional feed failures and a few other probs.Most of these were soon rectified, but a rep for trouble still hangs over the 11-87.
OTOH, the autos,Like Geoff said, are moreor less split between the 1100 and the Beretta 300 series, and the folks with the 390 and 391 series seem quite satisfied.
And lots of the 1100 folks have used them with lighter loads. 1 oz, 2 3/4 dram reloads are popular with the senior shooters I hang with.
With any of the gas guns, regular and correct cleaning and PM are mandatory. Over on Shotgun Report, they say that an 1100 will break down after 35,000 rounds or so, but that replacement of the O rings and some parts will extend that indefinitely.
BTW, those folks over there KNOW shotguns, and they are unenthused about the 11-87.