Also, I've worked in both Lua and Racket.

Racket's garbage collector is the only one I've ever used that actually made programs unusable.

Also, Racket's macro system feels like a mistake. While it's more powerful than most others, it's still rather incomplete, feels like a bad design, and ... well just look at the code that's used to implement the (sadly slow) object system. The code makes assembly language look clear by comparison. Dig under the surface and despair.

Scheme is very powerful, but in the end Lua programs are a lot more readable.