How does this compare to Heroku?

Neither seem to support WebSockets (though the Heroku article I found was a bit dated[1]) for the time being.

From the article, it seems like AppHarbor doesn't automagically pull in the dependencies from the package.json, which Heroku does.

Add-ons wise, there is a lot of overlap, but Heroku definitely has more at the moment.

Heroku lets you run one-off processes, which is nice for debugging. I couldn't find this functionality on AppHarbor.

[1]: http://blog.heroku.com/archives/2011/6/22/the_new_heroku_2_n...