In my own restricted view (I didn't play with may scheme implementations) Racket has some serious non-strictly-technical winning point that make it feasible for non-toy applications:
* Well-written, comprehensive language and package documentation
* Tooling
* Included libraries (example: I didn't expect racket to have libraries for imap... but it's there, in the standard package)
A nice development would be same-process parallelism. Afaik, at the moment you can have concurrent "threads" within the same process, but you need to spawn multiple racket vm processes to get parallelism (this is done "under the hood" by the racket vm, they call this things "Places").
* Well-written, comprehensive language and package documentation
* Tooling
* Included libraries (example: I didn't expect racket to have libraries for imap... but it's there, in the standard package)
A nice development would be same-process parallelism. Afaik, at the moment you can have concurrent "threads" within the same process, but you need to spawn multiple racket vm processes to get parallelism (this is done "under the hood" by the racket vm, they call this things "Places").