I have one - although the one I have differs from the one in the auction photos in that it has a fluted cylinder and is ported (S&W had 2 versions of the "Trail Boss").
The special designation - "Trail Boss" - means pretty much whatever you want it to... I don't think S&W ever gave an explanation.
But, I'll tell you my opinion anyways - "Trail Boss" to me connotates a firearm that is small and handy enough to carry while on the trail (such as in a backpack or on your hip) and yet have such devastating firepower that it would certainly be the "boss" of whatever task you set it against.
Feel free to dispute this if you wish, but it makes plenty of sense to me.
I can shoot full-power .44MAG ammo out of my pistol with no problem!. The porting REALLY helps control the recoil - of course this is offset by the huge tongues of flame shooting out of the ports, and it is the loudest thing on the range that I've yet heard.
I have some COR-BON .44MAG 305gr Flat-point Penetrator rounds that I have purchased for this gun - so that when I am finally ready to travel to Alaska I can feel a wee bit safe knowing that I now have a fighting chance to protect myself from a big, bad bear before it shreds me into taco meat.