Rated 3 out of 5 stars

Functionality is great. But When this addon is enabled, my memory jumps from 500MB to 8GB...

This review is for a previous version of the add-on (2.9). 

.. are you sure? quickFilters literally shouldn't take more extra memory above 300kBytes. it does not store the filters (these are already stored in Thunderbird independently from qF) and only adds a little UI for managing / creating and searching. it doesn't store any data structures except for the few settings in the options window.

Please raise a bug here:
http://quickfilters.mozdev.org/bugs.html