I sort of evaluated Typed Racket before I started writing lots of Racket code, and my experience was that "Contract" Racket (regular non-Typed Racket) was more ergonomic and idiomatic. I think the contract system is great and I use it, for example, when sending messages to Interactive Brokers:

https://github.com/evdubs/interactive-brokers-api/blob/maste...

This file just includes request message definitions and to-string (->string) implementations.

The overall program's performance is adequate for me, so if the contract system is causing overhead, I don't particularly care about it. Maybe that's a scalability concern for more performance-demanding programs which could benefit from Typed Racket.