The service is excellent. It just works and I can't discern any meaningful lag due to having my email forwarded so great job, Mozilla! However, in regards to this add-on specifically, I have a major complaint: I believe if you're going to have an auto-fill feature that places a glyph button in email fields, then the add-on should act like a password vault and let you click on the button > select the created alias you want > address is filled in the field. The add-on has half of that paradigm done well. It allows creation of new aliases and the option to take you into the "full" add-on management screen for more detailed changes. However, it's rather annoying to use a password vault that auto-fills but then when signing up with a relay address (i.e. my vault has nothing to remember yet to auto-fill), I have to go to manage my aliases and copy + paste them into the field. Again, though, I really value the service and it would be a 5-star extension if it let me pick and fill the alias within the current page's form.