One difference between Airstream and Chinook is that the former is a classic name, recognizable anywhere. Chinook is much less well-known, especially east of the Rockies (they are/were a west coast product). Of course, Airstream Class Bs are pretty rare as well. Both companies had a reputation for quality - or at least tried to have one. (Chinooks are awfully doggone expensive as newbuilds - not a lot of plastic & faux stuff in them.)
I'd be concerned about the rust underneath. East-coasters and Midwesterners can tell you all about the potential hidden problems from rust!
By "keep," do you mean keep one for yourself and sell one, after restoring both, or restore one and sell the other pre-restoration? If for yourself, only you can decide that.
Semi-disclaimer: I'm a former Chinook owner. Bought ours 8 years old, on a Dodge chassis, and after a couple years we were always getting it fixed. That may be a result of previous treatment, or just that the vehicle itself was old. We always had a heat-around-the-doghouse problem with it, among other things.
2020 Toyota Tundra CrewMax 5.7L V8 w/ tow pkg, Equal-i-zer
2020 Lance 2375