Rated 4 out of 5 stars

Without it, I'd never have written an extension. With it, it's as simple as can be.

Now with upcoming built-in publishing/updating to AMO (this site here)! All kudos to dandonkulous (see below):

This review is for a previous version of the add-on ( 

The push-to-AMO feature is now in the product and will be blogged about when we release the 1.0 final version of the Add-on Builder site in mid-February 2012 (about 3 weeks!)