How Sturdy, How Well Built?

[JFulford]

Hi, my wife and I are seriously interested in buying either a 2518 or 2720 trailer, (probably the KS/QS version) but we have a couple of questions that we can't trust a TM Sales Rep to answer honestly. We love the concept (we own a 2005 Hi-Lo trailer on its last legs) of a folding trailer! But we have a couple of concerns about TMs...
First, the shells are made of Styrofoam sandwiched between two layers of aluminum. How thick is each aluminum sheet (aluminum foil or as thick as a Airstream trailer wall) and how sturdy are the walls and roof? What happened when a sizeable tree limb fell on your roof?

Second, is the roof walkable and is there any wood (like luan) in it that might rot if a leak develops in a seam? This was a big problem with our Hi-Lo.

Third, new TMs are a lot more expensive (~$40,000) than many other trailers but are lighter and more aerodynamic than others. As owners, is the additional cost worth it to you?

Thanks in advance for your advice!