I think any new user would stumble on Path, OsString, and OsStr pretty quickly when working with files and directories. Rust tried really hard to avoid string related errors at runtime by not allowing strings to have invalid data. It's a defensible goal, and the cost is having multiple string types. And then they've got another doubling of types because of their ownership model.
It's not the choice I would make, but my opinion doesn't really matter. Real world strings (UTF-8, WTF-8, UCS-16, arbitrary bytes) don't follow the rules 100% of the time, so you're always going to end up dealing with that complexity at runtime in one place or another. I think you might as well have one simple string type and accept that. This is what Go chose (not that I'm a regular Go user either).
