1. I personally use VS: Code and Vim. IntelliJ has an officially supported plugin that I haven't used, but heard good things about it. The Eclipse project is considering making a Rust IDE but hasn't decided yet. VS non-Code should work now, but I haven't given it a go personally. On the "responsive" question, it's still actively being worked on, generally, so "it depends". We're actively investing in things being more robust.

2. We expect async/await to be stable before August, but as always, It Depends.

3. As you say, varies a ton by domain :) What I will say is, two years ago, crates.io had ~3000 packages, last year, 7500, today, almost 14,000. So we're getting there...