Cool, I wrote that article 18 months ago and I am glad to see it on HN. Chichen Scheme and Racket may have a lot more batteries-included type libraries available but Gambit-C with its custom Emacs support makes for a really nice developer experience. The ability to generate small native apps is great and it is a great tool. Marc Feeley also does a great job supporting it.
Since the article is 1 1/2 years old, you should check out the wiki http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Main_P... because only covered what I needed for my own projects in the article..