In the beginning it was a bit tricky because the migration to async was happening within the Rust community, so that caused some code churn early on. Lately though it's been smooth sailing.

I'm using tokio-postgres for my database library and both it and Rocket are async, so they synchronize very well together. I do not believe Diesel is currently async, but in either case I'm using tokio-postgres instead so I haven't had to look into how to integrate Diesel with Rocket.

Other than that, my needs were pretty simple and I used well-supported platforms, so I haven't really run into any major issues yet.