This comes up about every 4 months. Based on guns used for trap and sporting, the 391 by far. I prefer the feel of an 1100, but their actions aren't as dependable as a 391. An SX-1 is a great choice too if you can find a good one. Parts aren't as accessable as a 391 or 1100. They are about a pound heavier than a 391.
If you aren't going to shoot 20,000 rounds a year, the 1100 is fine if you clean it regularly.
Back when the Remington 1100 was all the RAGE...BROWNING introduced superior design and function semi-auto that was just too expensive to manufacture and sell at a profit. The Browning 2000 was made in Belgium and assembled in Portugal in the late 70's. Excellent quality and craftsmanship...a real "SLEEPER" if you can find one in nice condition!