fiberglass or aluminum siding

I have a 2005 Coachmen Cascade.. it is fiberglass sided.. this model had the option of aluminum or fiberglass when new... 650 more for fiberglass..

and this must be the reason my 7500 pound trailer is 8300 pounds... Empty.
beside the 2 30 pound tanks, battery... etc.

the logos and strips are all cracked/faded.. but the siding is still very white.. just some/most of the shine is gone.. I hope to wax it soon. and see if some of the shine will return.

I do like the flat sided look of the fiberglass. and the wife loves the Front Kitchen... 29FKCS. aka counter space. and room to move around.

If you want to renew the finish on your painted aluminum trailer, the best thing you can do is remove the oxidation. The easiest way I've found to do that is with either a phosphoric acid based product or using TSP. Lately, I use Jasco Prepaint Cleaner and Conditioner. I spray it onto painted surfaces with either a tank sprayer or a bottle sprayer.

The drill is to clean first, apply the Jasco and let it sit about 10 mins.. I then rinse it off using a scrub brush, lightly. It will remove almost all oxidation and the surface is then ready to paint or wax.

In my experience, it's the graphics that fade over time whether the trailer has aluminum or fiberglass walls. There is no way to prevent the fading; however, storing the trailer under cover will slow the degradation. This fading happened fairly quickly on the two fiberglass walled trailers I previously owned. Now, it's possible that the graphics on the trailers were of inferior quality. I don't know. This is what little I do know.

1. Depends on what you plan to tow it with. I would rather have a lighter trailer in order to not max out a TV (tow veh.) Alum is lighter than Filon and glue.
2. They both will age over time and decals are decals, they fade and peel and crack.
Keep both washed and well waxed and remove oxidation and they both look like new. It takes a little more elbow grease to keep the alum. waxed.
3. Alum is easier and less expensive to repair and can be repaired by anyone with basic skills . It can also be repaired in sections opposed to an entire side.
4. Its a little bit more difficult to maintain caulking around the corrugated aluminum but its not difficult, just takes a little more time .
5. Aluminum will not delaminate because its not glued to the trailer as Filon (seamless thin fiberglass type sheets) is. When water intrudes the Filon, the glue becomes saturated causing soft spots and delamination. This is very time consuming as well as expensive to repair. Repairs are made by pinch rolling the Filon because most people and RV repair facilities do not have the means (expensive eq. ) to vacuum bond it back to original condition.
6. Some prefer Filon because they like the smooth look and find it easier to clean.

I have owned a few of both and prefer aluminum due to the weight. The extra time cleaning it doesn't bother me. I'm fortunate to have my health to do it and that's what matters. All else is just personal choice.

They both have their good points and bad points. Just depends on a lot of factors and what you want to do, what you want to pay and even where you live.