I do like the fiberglass side. But I feel they need alittle more care then the aluminum. They need to be waxed more. Also if you look at all the park model trailers they are aluminum. Sounds to me aluminum would be your best bet for what you want. If I were to have a seasonal I would purchase an aluminum sided trailer to leave.
2008 FORD F250 FX4 XLT DIESEL
2013 JAYCO EAGLE 314BDS(Ordered)