Fiberglass VS Aluminum Siding

Today most RV Manufacturers are building Coaches with fiberglass or "Filon" siding. Is it really better? The smooth clean lines are attractive, it resists minor impacts and is easier to clean. The windows and doors may seal better to the smooth surface and if you contact a tree branch at the local campsite you may well get away with no damage. Cleaning an RV is always a chore and black streaks may be easier to remove from the flat surface. Now the drawbacks, filon built coaches have a large potential for leaking at the corner mouldings. Edge mouldings that get removed typically reveal large gaps that can let water inside walls if the seal fails. One method of avoiding this is to take note of top line units, most have a moulded one piece nose cap that covers the problem area. Another issue with fiberglass sided units is delamination; this happens when the siding and core of wall expand at different rates causing the siding to come loose from the wall. Any type of collision or delamination damage is very difficult to repair. In most cases a body shop needs to fill seams and blend color to get any kind of match. Now lets take a look at aluminum siding. First we think that aluminum's ability to breath through tongue and groove is a good idea. In many cases the siding is able to be wrapped around edges before mouldings are installed providing a backup to the silicone seal. When repairs are needed the aluminum siding is much easier to deal with, although color matches to older units are always a problem so avoiding the paint shop may not happen. As far a costs involved in repairing the fiberglass coaches would be much higher. Is fiberglass siding the way to go? We rarely see 20 year old fiberglass coaches in good condition.