I had a 2002 Sunline trailer (wood frame) that was just an excellent trailer and held up to many miles of towing. I think it was better insulated than our 2014 Winnebago Minnie (aluminum). But I appreciate the ease of cleaning the smooth sides of the Minnie vs. the aluminum siding that was on the Sunline. It really boils down to the quality of materials and construction and you have to decide how much insulation you want, so compare the R factors of the sidewalls and roof.
It seems to me that many of the better 4 season trailers still use wood frames...but I'm not really up to speed on what's available.
You can get a lot of years out of most trailers if you maintain the seals and prevent any water leaks.