I feel any perceived longevity advantage of early buses over Vanagons is
due to low cost of engine replacement.  A sick sixties bus can be healthy
again for a few hundred dollars.  When a Vanagon goes down, it stays down
unless a pretty substantial investment is made.  The Vanagon body, I think,
stands up to rust better.  Cloth interior gets raggy faster than vinyl, 
but a nice cloth interior is nicer than any vinyl interior.

Interested in other opinions about best bus for the long term.
B.