Any academic research extensions deserve 5 stars.
One of the best tools if its topic especially for scientist and knowledge workers. Provides a good usability experience after asking for getting the captchas removed which really annoyed me.
Collaborative features could be more flexible.
Try to understand the concept behind this service and you'll be happy.
Since the first release I have been using the plugin. I did not have any difficulties like others. It is simple and it works. I recommend to use it if you are working with BibSonomy.
This addon is small, but very useful. I've always used the BibSonomy bookmarklets so far, but this addon is just a perfect replacement, which uses less space compared to the bookmarklets. I'm using it now for my everyday bookmarking activities. Thumbs up!