From
what I've read, Valiant has changed a few things including not using
fire-retardant resin
any more.

a quick study you are, doguies, that happened about a quarter century ago.

...Passports or Valiants either one, and so
can't comment on thier relative build quality.

Passport quality is excellent, as is usually Valiant.

But one thing I like about the Valiants is
that they sail pretty well for their looks and their capacity

nah. They sail okay "for their looks and capacity" but less so than other boat
of similar looks and capacity.

At times past I've criticised this general type as "faux Colin Archers"
(which they are)

A Passport looks like a Colin Archer? Since when?

And Valiant only looks like a Colin Archer from the deck up.