Rated 3 out of 5 stars

Very interesting view but there are some drawbacks:- too much broken features when using that addon (message navigation, attachment preview — said as highly not recommended —, simple addons such as ThunderBrowse, ...)- takes time to load a message- not enough configurable- based only on messages IDs ? Seems not to use subject messages... it doesn't work for me on a mailing list mapped on a forum (messages IDs are probably wrong) whereas TB manages to group those messages when using TB built-in group feature.- does not work well when using "sort by grouped discussion" TB feature- unable to disable feature without disabling the plugin and reloading TB- integrated Contacts addon which provides an important feature is not usable with TB 5 and the project is no more continued. Conversations should retrieve the code and include it, or maintain Contacts as contributors.

EDIT: didn't see possibility to reply, so editing my first review.
Thanks for your answer.
- I'll fill the github wiki for broken addon,
- on the FLOSS manual, group by sort is used, I even understand the doc as it is required.
- I understand the wanted simplicity but being able to customize/configure the addon behaviors is not adding complexity, only flexibility :)
Thanks again, and greetings for the work done and the documentation quality on GitHub.

This review is for a previous version of the add-on (2.0.8). 

Hi, thanks for the feedback.
- about broken addons: see http://wiki.github.com/protz/GMail-Conversation-View/faq
- performance is indeed an issue, we plan to improve it over the summer
- threading issues : see http://wiki.github.com/protz/GMail-Conversation-View/faq
- we don't plan on supporting every single Thunderbird feature, and sort by group is one of them that doesn't map well to the conversation view: I suggest you uninstall the addon if you plan on using group by sort often,
- contacts is not vital, and the addon works fine without — I myself have stopped using contacts
- we want to keep the addon simple and we do advertise a simple, efficient way to view your emails; adding a zillion options is not part of the plan!