However, there's also something mentioned in this announcement: cargo-check. In terms of the "I'm building a project and I don't want my builds to be slow," I think that cargo-check might even be more important. cargo-check relies on an important insight: many times, when you're compiling, you don't actually care about producing a binary, you care that your code passes typechecking and other passes. cargo-check basically runs those things, and doesn't produce the final binary. Makes sense?
On top of that they have the financial backing of apple.
I got the impression that Linux support is more of a "here iOS/OSX develoeprs - we're aware you don't actually run OSX on your servers so you can share code between client and server now". I was not aware Apple wants to push Swift as a cross platform language.
If it was and their commitment looked credible (ie. they start porting tools like integrating debuggers and stuff on other platforms as well) I would definitely consider it.
I've been following Rust from sidelines before 1.0 and from my perspective there are advantages but I can also see a lot of pain in porting stuff and moving over and I right now the benefits don't outweigh the risk and cost for me - but having a fast build system (which implies incremental recompilation) along with a default package manager (which it already has) would be enough for me to start working with it seriously.
It's kind of sad that building code is such an instrumental part of developing C++ when it's just about dealing with technical issues of the compiler/language/tools and not the problems I'm trying to solve - anything that gets me away from that while leaving me with similar level of memory control and portability is a big win for me.
So when should I be looking back at it ? 6 months ?