I thought it was worthwhile to start another thread on this topic, so here goes. First off I am a retiree and not affiliated with any company or employer whatsoever.
I am surprised that over the 8 years I've owned this trailer, and have worried all that time over the graphics slowly peeling away, that there was no information anywhere that this stuff even existed. The only advice being to use the Aerospace stuff, which I did, but my experience is that it only slowed down the deterioration. And I say "maybe". I think that what happens to decals is that they get hot from sitting in the sun, and the glue that holds them on gets soft, and they peel. I am hoping that the Clearshield will stop that (so far appears to) since the shield it forms is slightly bigger all around than the graphic, thus the graphic would have to pull the clearshield away from the filon exterior of my trailer. I don't think it can. As far as appearance, other than the decals look much better, you can't really see the clearshield unless you lay your head on the side of the trailer and peer down the side. Then you can see it.
My exterior is "filon" which is supposedly like fiberglass. It's a Kodiak by Skamper. I don't know how long it will last, but looking at the final product it seems the answer is a long, long time. I can't find any reviews of the product, I suspect because us non-pro mere-mortals aren't supposed to be using the stuff, only a shop.
http://www.lexjet.com/ apparently will sell you a quart. Maybe other places. Amazon will sell you a 55 gallon barrel for $4500. The local graphics guy sold me 1/2 of a quart for $25 which did 2 coats on all the decals on my 24 ft trailer with a bit left over.
One last point, get yourself a small roller, small enough to paint the decal with maybe an inch overlap. If you decide to use a brush, like I did, start at one end of the decal and paint across to the other end. The stuff tends to set up faster than you might think, and you don't want to be going back over the areas you've already painted with the brush, as it tends to leave brush marks. However, that said, those places where I did that flattened out, and I can't tell those areas from areas where I was purposefully methodical.
Clean up is a breeze, as the stuff vanishes when you hit it with water. Hint hint! Make sure it doesn't rain for 2 hours following application!!
http://www.marabu-northamerica.com/products/product-overview/liquid-coatings.html