Sounds like a fair price Slugo ....in my area, new, they're selling for about $1,900.../ist is $ 2150 or so now ...and the last used one I saw was about $ 1,350.
Not that you haven't ...but I'd take it apart and check it. Look for obvious abuse.....once you take the forend nut off...and slide forend off...take barrel off - hold the bolt release back...and the top of the reciever comes off as a separate piece. At that point you can slide the whole bolt group out...and if you punch out one pin ...you can drop the whole trigger group out. If owner lets you / or shows you ...bolt group comes apart in about 10 seconds...pull out bolt retraction lever, depress and remove stud holding firing pin in ..remove firing pin ...and pull pin and remove bolt head..and check the recoil spring inside the bolt assembly ...( make sure it clean / no burrs...) ...check the rails make sure no burrs.../ same thing on trigger group ....easy to do / easy to check.
check the barrel to receiver connection ...should be clean and lubed...
Gun should come with 5 chokes ( Cyc, IC, Mod, IM, Full ) and crio barrel gives me a little tighter pattern than my other guns so I shoot one less choke than normal in this gun ( so Cyc for Skeet, IC for 16 yd Trap, etc..and sporting IC mostly )...
Gun is real light ...so I find the 28" barrel a little too short and too light ...but at 6'5" and 290 lbs ...I like heavier and longer guns..../ but for resale the 28" in this gun is not preferred / longer sight plane on a 7 lb gun helps smoothe out the swing on it ...and its only 0.1 lb heavier I think. It was available in 12ga in 28" or 30" ....and it should have the longest LOP insert in stock and the comb insert that is level with the rest of the comb ..giving it some drop at comb ...there are 2 other recoil pads you can buy and 2 other comb pads you can buy ( about $100 each ) and recoil pads for lefties as well ... Personally, I like the highest of the comb pads...makes it virtually a parallel comb gun.
Same gun is available in 20ga...but only in 28" barrel ...and it feels way too short for me.../ good training gun for the kids...
My 12ga gun will cycle any shell as long as its 1200 fps ....7/8 oz, 1 oz, doesn't matter....but to make sure it does that ...gun needs to be clean and well lubed. But they shoot so clean ...I've run my gun for 1,000 shells or so over a weekend, without cleaning, and no cycling issues. However, it only takes 10 min to disassemble it --- clean and lube it ---and put it back into battery. In my 20ga - all I've shot in it is 2 3/4" reloads at 7/8 oz and 1200 fps...
There are not many around used ....but at $ 1250 used / even if you were able to ask up to $ 1,400 for it used ....there are a lot of gas guns on the market your potential buyers will buy new ...for less money - and pretty nice guns from Beretta or Browning as an example. I don't know that you can make a profit off it ...vs buy it and keep it, if you want one. I think on this gun in particular ....because of price, its a small market / a lot of guys would like one ...but not at $ 1,250 plus...they go to something else...
Check out the specs online ...Benelli has a good website....and they have an upgraded model on the super sport now too ...I forget what they call it right now.
I like my supersports a lot ...I use them primarily as rain guns / or travel guns ...or training guns ...or when my rebuilt shoulder is bad and I don't want to shoot a 28ga or something lighter. The supersports are both semi-autos I'll keep long term ( mine are about 8 yrs old now I think ). I bought the 12ga first ...after I fractured my shoulder blade...and I couldn't shoot my 12ga 8 1/2 lb O/U Brownings ...so I needed something lighter ...and some kind of semi-auto to compete that summer in sporting clays...and it allowed me to do that /while I was healing. I still shoot it 4 or 5 times a yr...just because...or when it rains. I travel with it ...because it does a lot of things well....some clays, some hunting, some Trap or whatever...and I only need to take 1 gun on airlines ...and its not a $5,000 gun that I would cry over, if it got beat up by airlines...
that's my 2 cents