This is such a subjective thing. We have a 2000 Cardinal and have used it a lot. We have had a couple of serious problems with it caused by squirrels and a water leak. The leak was due to a tear in the rubber roof after hitting a branch. I have fixed both and we have installed new floors and upgraded our furniture. The unit is solid and we plan on keeping it longer. We are about to leave for Arizona with it and this summer we will be going up to Yukon. We live in Southern B.C.
Bottom line is a used older trailer can be just fine. It will be a lot cheaper then new and therefore there is money left to fix things like a furnace or water heater if they break down. If the trailer is solid it can last for years, if it was not well made to begin with it is not worth the repair. Older units will not look as shiny as new so that may be important to you as well.