If you have an interest in seeing Restic implemented in Rust, I would very much like to see the development of alternative clients which strive to be compatible with the on-disk repository/storage format.
The more active implementations, along with the requirement of interoperability, will only strengthen the specifications. When there’s one implementation, it’s just documentation. When there are two or more, it becomes a contract.
I personally have no favorite between Go and Rust. I’m slightly more familiar with Go at the moment, which makes the Go implementation a little bit more accessible to me (in terms of reading the source). It looks like a few design choices were influenced by the Go ecosystem (single binary distribution, choice of crypto based on availability in Go’s standard library, etc.). It would be interesting to see which design choices Rust’s ecosystem would influence.