Rated 4 out of 5 stars
It's really worth checking AMO's recently updated list occasionally otherwise I would have missed this small gem. Biscuit is potentially a 5 star extension but has some interaction issues which I would like to have sorted out, primarily among them a more convenient way to select which cookies get deleted and not.
Here's a list of humble suggestions:
1) Allow to toggle the preserve state by hitting the space bar (AFAIK it's not used on any platform in the cookies window)
2) Allow to toggle all cookies from a specific domain by selecting the domain under which they are grouped in the cookies window
3) Allow to preserve all cookies from the current domain via the regular interface. This could be achieved via a button or an additional entry in the Tools menu, nothing fancy though, just an on/off switch would suffice for me personally. I imagine this to be a blanket approval/disapproval, i.e. not only for the current cookies present when toggling the switch but also for future cookies.
4) Don't preserve session cookies by default as they get deleted anyway at the end of the session.
Anyway, thanks again for this privacy improvement. And sorry for the lack of paragraphs, AMO gets rid of line breaks when after editing a review. :-(