I like the "Unusual other syntaxes: Use a more unusual syntax which no other construction in Rust uses, such future!await." [1] (or future@await). It makes sense because it is in fact something different than what exists anywhere else in Rust so it should receive a commensurate syntactic treatment. This was written off pretty quickly in [1] but it appears the most consistent with language philosophy -- specifically because it's inconsistent with any other language features it should get inconsistent syntax. I think that's what's throwing people off in this process: an attempt to impose 'consistency' on something that just isn't. As such, it'll never feel natural to co-opt existing syntax. Let's embrace it's inconsistency and introduce new syntax.
It supports '?' and '.' natively, and offers a path forward for new similar kinds of postfix operators without making more field names off-limits -- even the expr@match { .. } postfix expression thrown around would fit well. The @-prefixed postfix operator would return a value like all other expressions.
tl;dr: Either the syntax is inconsistent or the semantics are, and IMO, the former is preferable to the latter.
Either way, cool to see this feature moving along! Looking forward to using it no matter how it's spelled out haha.
[1] https://paper.dropbox.com/doc/Await-Syntax-Write-Up--AcIbhZ1...