Purchased a Raptor 3712 last fall for all season usage. We have been very happy. So far the only downfall (for us) is air gaps in the slides. Camping at -20, you could sure feel the draft. Easily fixed by "packing" round the bottom of the bedroom slide (most gap) with old sleeping bags, and adding an electric blanket.
Otherwise...we have used and towed it in some of the worst environments and it's a trooper. Actually spent Christmas weekend in it with -15 degree temps.
The only physical problem has been the GFCI outlets stopped working. Dealer fixed immediately, and has been great.
This is my third trailer and It feels like a well made unit. It certainly has surprised me how "understanding" it has been during cold weather. No problems with the slides, generator starting, or batteries.
Friends of ours have the Raptor TT model and have also put it to the test over and over again. They too have been pleased with the reliability.
Winter camping is the one reason I'm glad I don't have the bedroom slide in my Raptor 3814. I've been planning on pulling the underside covering and seeing about adding more insulation up in there, plus covering the garage's underside area, and maybe even add some insulation board inside cabinets. I'll probably do that this Fall after I finish rebuilding the motors in the snowmobiles.
I also figure that for really cold temps, I will keep the slide closed, at least at night, to conserve heat.