[hajile]

Nobody would consider Chrome or Firefox to be immature or lacking polish because they have replaced entire compilers several times over the past few years? I don't have an exact count, but they probably do this every 3-5 years which puts them way ahead of Racket.

I'd also note that Chez Scheme was a commercial implementation bought and open-sourced by Cisco. It wasn't something they threw together. Because it is a complete scheme v6 implementation they are building on instead of rolling their own implementation in C. Coding against a stable Scheme API has to be easier and less buggy than what they had before (not to mention Chez being much faster at a lot of stuff).