It took me about of month of writing async rust (coming from a solid sync rust background) to feel comfortable. In that first month there were definitely a lot of inscrutable issues (fortunately the tokio discord was very helpful).

But now it feels productive, and if you're totally in the async world, it all works pretty well.

The lack of async traits is my main pain point today, but you can mostly work around that with the async_trait crate. Generally it's been slow progress on usability but I think it's in a much better place than it was a year ago, and will clearly be better in another year.