I'm using Loco a lot since half a year, and have contributed some upstream patches. It's definitely not Rails, but where I was always afraid of refactoring Python applications, that fear is pretty much gone with Loco/Rust. That, and the incredible performance make me enjoy it a lot now. You pay extra with development time, but you get it back with long term maintainability.

My main remaining gripe is the Rust compilation speed...