I really like this extension. It pretty much has all the features of other ao3 extensions you may find on here and more. I especially like the fetch marked for later/bookmarks option and the metadata it collects is incredibly thorough. This being said it is very laggy on AO3. Badges take a long time to be added after selecting them and it significantly slows down scrolling, especially if you have more than one tab open. I also found the dashboard UI a little confusing (it took me a lot of pressing buttons to figure everything out), but I don't experience any lag there.