Look at the R values in your selections. Check to see if the dump valves are in an insulated compartment. Are the tanks insulated? Get dual pane windows. You need to read between the lines as they say when deciphering what is meant by all season rated. Lots of smoke and mirrors in the RV industry.
Living in Oregon I would recommended Northwood Mfg or OutdoorsRV. Only because they offer TT/5'ers for the northwest usage. There are others out there as well that are just as good for 4 season camping. But buying local is better in that if you have a major problem the factory is close.
Forest River has a plant in Dallas Or, also. I know they sell Wildcat Maxx. Looking at the brochure online they seem to be well insulated.