I have a 2013 Apex that was bought in 2012. It has been in hurricanes at the beach, and rain so hard you couldn't see the ocean, or the camper beside of you. It leaked ONE time. the wind was blowing the rain UP, Yes I said up. One of the speakers didn't close quick enough, and it leaked thru a speaker. NO WHERE ELSE. and didn't hurt anything since there is no wood in the walls. Nothing to rot. It is now 5 years old, and looks like new.
As for insulation and weather. The APEX has AZDEL in the walls. AZDEL gives the TT 50% more insulation R value than TTs with out it. I know mine stays much cooler than the Fleetwood it replaced. I can't speak to the construction of the Lance.
I will say. I had 2 catastrophic tire failures. Tires completely disappeared. The only damage to the TT was that a piece of molding was bent a little, and one of the low point drains caps spun open. But not off.
So in short. I have no complaints about the APEX. Just bigger than I want. Sleeps 10, and I don't need that any more.