I've been with Racket for a while, but made the switch to Urlang so that I could guarantee that more people could easily play my game (and also I don't have a compile farm to run out for each arch). I'm interested in the Guile Hoot thing, but no browser I use currently supports it, so will have to wait a bit. Nice list!
Racket is famously a "language to create languages", so Urlang is leveraging that capability inside Racket. It isn't Racket (or Scheme, even). The author calls it "JavaScript with a sane syntax", but it's a lot more than just a direct translation -- you can have macros and the Racket editor understands the syntax appropriately and does checking at compile time. Taking advantage of the macros, it also offers rich loop constructs and other conveniences. Number one advantage for me is I can use standard JavaScript libraries like three or mithril.js.