I like Raynor's best steel with no windows. I have a 900 sq ft garage with 2x4 insulated walls and R-50 or so in the ceiling. I live in Wyoming and it will hit -40 F. MY garage got gas heat only three years ago, but before that it would stay above freezing regardless of the temps. Before I got the Raynor insulated doors I had single wall fiberglass doors, and the garage would freeze at approx 10 degrees. I have had zero problems with these Raynor doors.

We have haas 2000 series, with temps -10F the garage stays well above freezing.

In general polyurethane core insulation is better as the polyurethane is poured and cured (glued) inside the steel garage door sandwich panel. The polystyrene insulation is softer and loose in between the steel panel. A polyurethane core insulation is more rigid. Check out http://www.overheaddoor.com/garage-doors (Thermocore) and http://www.clopaydoor.com/residential/buyingguide/intellicore (Clopay Intellicore).