Im looking for a new semi automatic shotgun and i believe the remington 1100 and winchester sx3 are my best options. I cant decide so whats your guys opinion? If you know of any other good automatics under $1000 be sure to include those too.
I personally love Benelli! While there are many nice shotguns out there I think it is the best shotgun for your money... They just simply work and keep on running! I can't knock either of the guns you named as I also have a Remington and have some trigger time on an SX3. I would never discourage anyone from buying either. Your purpose is important for you choice however. Beretta is another nice brand you didn't mention.
Anything hunting related go Benelli! I have personally seen a little over 6 thousand rounds run through a Benelli in one day and it never quit. It also had seen thousands before that day... I saw a lot of guns that received a crazy high round count on a very regular basis and Benelli was the shinning star of all of them. I just can't say enough about them...
I have two 1100's in 12 ga. One is a 3" magnum, smooth bore, with rifle sights, set up as an HD / Slug gun and the other is a stock 2 3/4", 28" mod. VR barrel model. I have put many rounds through both of them and have had them for many years without any problems. I have replaced the gas rings a couple of times on each one. I love Remingtons. Especially the older ones.
In general I prefer Benelli, Beretta and Remington in that order and own all three. Based on 1100 vs SX3, I would probably go with the Winchester if I was buying new. At 51 I doubt any new semi auto I buy won't be a Benelli unless I get a Beretta for clays.
You should state how you want to use it before you get opinions.
There is also preference. I want my wife to switch back to Beretta but she is so enamored by Benelli since 2012 that I don't think she would enjoy the Beretta as much as a Benelli. She shot a Super Sport that had over 10k rounds through it with zero cleaning. I can't force her to love Beretta and I use Benelli more then the others.