The Remington is my suggestion. There are a number of small differences between the 1100 and the 11-87, but the main one is that the 11-87 has a valve arrangement on the barrel to compensate between 2 3/4" shells and 3" shells, and still shoot both reliably. With the 1100 Magnum, there would be some light 2 3/4" loads that would not cycle the action. I don't believe the 1100 is currently marketed by Remington in the 3" version, so you'll have to find a used one if you opt for the 1100 3". As far as the 3.5" SuperMag, it is useful if you are limited to steel for goose, and want the extra lead for turkey. If you use HeviShot in 3", you won't see much if any performance difference to that of 3.5" steel. I have 12 ga Remington automatics in all three chamber lengths, and this is the performance I have observed. (If you opt for the 3.5" chamber, get the 11-87 over the 870. That 870 in 3.5" hurts!) By the way, Remington has a "barrel seal activator" that shuts off the gas valve altogether in the SuperMag, allowing reasonably reliable cycling with 2 3/4" shells. There is still an occasional feed malfunction due to the short shell in the 3.5" length action. Too much room allows the short shell to flop around a bit.