The title is misleading since the blog author admits to not having tried Racket recently. IMHO, Racket fixes the author's key complaint about documentation by having a Guide (separate from Reference) with many examples: http://docs.racket-lang.org/guide/index.html
Since Racket isn't Scheme, it also comes with more data structures built-in and there's on-going work to better support numerical computation.
Yes, Racket is probably one of the best languages out there. And the documentation for the core language and standard library is excellent (Racket guide and Racket reference). But I think the author is talking about the PlanetT.