I have to say, as a C++ developer, I'm really impressed with Rust's progress in the last year. Creating a browser rendering engine is a complicated task -- it's a very strong proof that the language is practical. Rust also seems to have a friendly, engaging community, and leaders (e.g. pcwalton) that are fair-minded and that invite and inform rather than scare away. The docs are nicely presented and informative. The language feels fresh and modern. The build and library discovery story is 10x better than what C++ offers.
In short, there's a lot to make you want to move over. Still, I a) have a ~90K LOC code base in C++/Obj-C that I'm not going to abandon any time soon, and b) after having gotten burned (in Haskell) by the "more purity or strictness (in the conventional, not evaluation, sense) is always better" argument, I'm waiting to be convinced that having a more picky compiler actually helps rather than getting in the way. As mentioned above, projects like this certainly make one more confident that it does help.
In short, there's a lot to make you want to move over. Still, I a) have a ~90K LOC code base in C++/Obj-C that I'm not going to abandon any time soon, and b) after having gotten burned (in Haskell) by the "more purity or strictness (in the conventional, not evaluation, sense) is always better" argument, I'm waiting to be convinced that having a more picky compiler actually helps rather than getting in the way. As mentioned above, projects like this certainly make one more confident that it does help.