Ok, the Remington 1100 was introduced in 1963. It quickly came to dominate the clay sports where folks used semi autos. However, when the Beretta 390 came out the 1100 just as quickly became displaced.
The old A390ST that I have is a treasure. It fits me well, and can be tuned to fit most folks of reasonable proportions. It is so absolutely reliable that it has pretty much ruined me for anything else. It is also very easy to break down and clean. The wood on it was just too pretty to beat up in the field, so I traded a Remington 11-87 in on one of the "Wal Mart" guns. I bought it at Bass Pro though. It has been immersed in black gumbo mud, whacked against trees, dinged, banged, etc. But it has never failed me. At $549.00, give or take, it is one of the best values in an auto loading shotgun available today.
There is a great deal of discussion about the difference between the 390 / 3901 and the 391 series. Some folks think that the 391 is a great improvement... I personally don't. They added some complex stuff that really did not improve anything and made the gun a lot more trouble to break down and clean.
Here is a very good discussion of the whole thing:
http://www.chuckhawks.com/beretta_300series_mystery.htm
Now, everybody pays their money and takes their choice. Some would rather eat worms than give up their 1100's. That's ok, but for me I find the 390 / 3901 to be far more reliable. The 1100 design is nearly 50 years old. In its day it was about as good as it got. I personally don't think so anymore.
