I'll throw some incite in here. I live in eastern Canada so we get lots of snow and freezing rain. i have a set of steelies that i keep a dedicated winter on. Also i always had weight in the box. I used train ties cut down to fit perfect in the box. The first 3 winters i ran the Cooper M+S and they were excellent. I only switched to the duratrac because i didn't like the look of the small cooper size and they were decent in the snow. This will be my second winter on the duratracs and so far so good. The only change i would have done now is stud them.
The cooper was also studdable but definitely didn't need it. The duratrac is excellent everywhere but glare ice so when i go to replace these i will either try something new or throw a set of studded duratracs on this time. All though cooper makes that new AT/W that looks interesting, and i have seen a few other newer winters out there that look promising.
the pin weight on the new trailer is 4300lbs, so that's the most ive had in my 2500, upgraded tries, and sumo springs and the truck didn't even sag before i installed the sumo spring. I was quite surprised.