I know that the Quicksilver frame is all aluminum, but not sure about the roof surface. The brochure says, "Alpha Superflex Roof w/12 year Limited Warranty (more durable, less chaulking and streaking)"
Also, the Quicksilver just went to Fiberglass siding this year because they say that it's more durable against small impacts such as rocks and baseballs, and won't dent. They say that the aluminum sides dent easily and are nearly impossible to repair.
I know the ATC feels stronger to me when I walk through it, but the ceiling is much lower, not allowing much versatility for furnishing in the back. We would like a couch or dinette under the happijac bed, but there's not enough ceiling clearance to get it up and out of the way to walk under. We want to delete the dinette next to the kitchen and have a couple of swivel chairs there.