Back to beta-phase claim, you're saying the core features and compiler of Rust are no longer in development or testing? Totally stable now with only extensions, library features, and optimizations being added? If so, that's good news and I'll drop that claim in the future. Otherwise, it's in the beta phase. Another hint would be existence of any bugs with core functionality in your compiler or libraries.
Again, though, if the spec and core functionality are frozen with all bugs fixed then I won't call it beta. Is it there yet?