Thanks for your kind review! Things like this always cheer me up.
Most of the bad reviews are due to the history of Gesturefy.

Version 1.0 got a lot of hate, because new add-ons could not (and still cannot) compete with the old/previous add-ons users were using before Firefox disabled the old extension API.

Other bad reviews for Version 3.0 are related to a decision I made moving away from 4 directions (up, down, right, left) to completely free drawn gestures. At the beginning of the release there was only one matching algorithm (strict) which some existing users didn't like.

I'm glad that most people none the less value free and open source software and adjust their expectations accordingly.