So what do you think of productivity in Rust vs python/ruby/js? Is it a lot slower to implement something in Rust? While it has a lot of high level features, it doesn't strike me as particularly concise compared to, say, haskell or python..
Conciseness isn't really an issue IMO. You can type fast, and your IDE can probably autocomplete. Note that the explicitness in Rust also makes it harder to make mistakes, so I feel that some extra code here and there isn't a bad price to pay.
As for conciseness, I do think it matters; it's not about how fast you type really, but how fast you can read what you wrote a week later. But conciseness is perhaps a bit of a blunt term, and maybe needs a bit of qualifiers. Now, take this with a large grain of salt due to my very limited knowledge of Rust. But, say, for a short program/script I guess python "wins" clearly since you can just let it bomb out with a stack trace if something goes wrong, whereas in Rust you have more explicit type conversions (.to_string() etc.), and you have to handle errors somehow, even if it's just with try!/unwrap() etc. which adds clutter. But for a larger program, maybe the difference isn't so big anymore, since Rust, unusually for a "close-to-the-metal" language, has a lot of higher-level functional-style features, and for python you probably want to handle errors in some way anyhow?
Eventually you'll learn to glance over unwrap() and try!() (well, unwrap() less so, since it's a bad idea to keep it around in your code) and the code you're reading becomes pretty straightforward to read.
My one annoyance in reading Rust code is that because of type inference (which is a super awesome feature otherwise and this annoyance is nowhere close to being enough to make me dislike it) you sometimes don't know the type of the thing being worked on, so getting an idea of what the code is doing is harder (of course, python has the same issue with dynamic types). I've recently started using YouCompleteMe, though, which has pretty decent "Jump To Definition" support which lets me quickly jump around the types and figure out what's happening in such cases.
It's a much younger ecosystem, so there's not always a library though. Then it clearly takes longer, because there's a lot more to do. We do have a pretty respectable number of libraries for our age though, I'm constantly surprised at what DOES exist.
