We don't have a whole lot of data, but generally faster. I can't seem to find the blog post now, but someone ported their raytracer from C++ to Rust, and the compile time was... half? I think?
[1] https://ruudvanasseldonk.com/2014/10/20/writing-a-path-trace... (See "Performance")
Right now, Rust only builds each crate in paralell, we don't support incremental re-builds within crates. There's an RFC already though, and build times are gonna be a big focus of the next release cycle or two.
Huh.