I haven't used Rust, but generally speaking wouldn't you say that safety in some sense includes the other nice features? For instance, if it were safe but not fast (like, say, a GC language) it wouldn't be useful. So it has to be safe and fast (which it sounds to me like it is). Okay, so what if it were safe, fast, but a real hassle to use? Well that's not very useful either. So it has to be safe, fast, and usable. Just like Moxie's approach to security: focus on usability, so people actually use the damn thing. And it sounds like all the other nice features make Rust more usable.