Rated 4 out of 5 stars

It is a great and powerful addon. I wouldn't know what to do without it.

But it also isn't somethings i can recommend to someone without any web development experience (knowledge of js/css/xpath). And still it isn't very user-friendly...
- after using it a very long time, i just learned today that it supports other types of locators (always hated xpath) and other useful stuff. Sure, i may should have read the manual (or the forum, since afaik there isn't any manual) but the gui definitively isn't self explaining...
- you have to dig in the addon's config files if you want to change existing alerts
That 2 points annoys me most and are the reason for only 4 of 5 stars.

edit: aww yes, i missed that small blue text link just above the also blue date. I'm somewhat sure it wasn't always there :/
Guess thats reinforces the point about the "not unfriendly gui". I'm curious about the coming updates.

This review is for a previous version of the add-on (0.4.6.20111013.1-signed). 

What do you need to edit the config files for? Most of alert attributes can be edited in your inbox (except URL). It is likely that you have not noticed the "- Options" when you click to expand an alert.

RIght now it is targeted towards power users. Work to make it more "user" friendly is being done. There is a major update in making.