We went thru a trailer selection process a few months back, and after dealing with delamination on our motorhome, I wanted either "stick and tin" or Azdel.
If you're really looking at fiberglass, look for Azdel construction.
Most trailers that experience delamination have a wall construction of filon (fiberglass) that's glued to luan, which is glued to an inch or so of styrofoam that straddles/fills the aluminum frame, and then another sheet of luan glued to that to form the interior wall.
Luan wicks water like crazy and pretty much dissolves wood when it dries out, and that's where your delamination becomes visible. By the time you can see it, you can't fix it. All you can do is inject lots of adhesive or epoxy to try and fill the void and rebond the filon with the foam, and what you use has to be able to bond to the foam without dissolving it (contact cements will eat it away...). The bigger problem is you've compromised the structural strength of the exterior walls when part of the sandwich fails.
Azdel construction uses a Filon/plastic/foam/luan sandwich. By taking luan out of the exterior layer, there's no wicking of the moisture, and no disintegration of the structure. There's always the chance of the adhesive giving away between layers, but you can re-glue filon to Azdel without worrying about what type of adhesive you're using.
The brands using Azdel are growing. Had Grand Design offered it, we would have looked at their laminated trailers. Instead, I went with stick and tin knowing that I could repair any water damage with the tools in my woodshop.
