she's a mid to late 90 ( 94-98 or so IIRC ) unit with a 6 cyl 401 engine. about 90 pto hp. the S indicates a series progression. for instance looking at the thousand series fords you have the 5000, 5600, 5610, 5610 II, and 5610S.. etc..
the S models were mexican built. that turns some people off for whatever reason, perhaps a quality issue on some things. generally the S models were more economy and spartan / plan, oweing more to their old 5xxx/7xxx ford model lines of square straight hoods made of metal instead of plastic, non-flat op platforms where you had running boards and straddled the tranny like most older tractors.
I actually PREFER all of those 'features'. I have a NH 7610S and love it. about the sme power range, mine happens to be a hair newer at a 2000 model.. I've looked at 7810s modes and have driven them... for all intents and purposes, they remind me, again, of my 7610s with a couple more injector lines.... should have about the same tires 10-16 and 18.4-34, with mfwd as an option, plus the 'newer' closed center pilot operated hyds, rops should be standard, and should have something like the basic 8spd twin stick crashbox tranny shared by many of the the 65+ 'thousand' series tractors. I good basic tranny with decent forward speed options and a fast-too fast or slow-too slow reverse..
I have plenty of hours of use on my 7610s mowing, have only driven an 7810s a few times.. RickB would probably be 'the man' to fluff or straighten out the rest of the info, in case I have mis stated any of it, and i'm sure I've left out plenty of details as well.
as for pro's of a tractor in this class? it's alot of hp, and in a pretty basic, sturdy package.. not alot of stuff in the way if you need to get to something to work on it... if you have a high hp need like a big disc or a batwing mower.. should work out good. Our local county maintenance used a FLEET of 7610s, and for sure had a good handfull o fhte 7810s, as well as the 56 and 66 's' models as well.
con's? well.. it's a big tractor.. if you need to work in tight quartes in the woods... may not be best choice. hyds are ok, might want the aux pump if you run a laoder.. or at least a pto pump. front axle should be MORE than sufficeint for a heavy loader. some people don't like the 8spd crashbox tranny... for me, it's fine.. I think it's one of fords (legacy ) more robust designs. individual operators will have different opinions. also.. some people prefer flat operator platforms, not straddle-the-tranny setups with running boards on either side. as mentioned. i actually "PREFER" that.. so.. YMMV.
soundguy