Avion is much heavier, some ‘70’s Airstreams had frame issues- rear bath models after they added a gray water tank. Google airstream elephant ears to see what to look for in terms of factory repair.
I like the Airstream suspension far more than the Avion, though they do wear out, the rubber just deteriorates. Replacement is not hard, but something to look out for.
All of that said, as a useable RV, the Avion is a better value. As an investment, the Airstream, though I think any RV investment is tricky, unless you do it as a business.
-- Chris Bryant