Rated 4 out of 5 stars

1) It's buggy.

When I have several Firefox browsers open and I read or delete feeds in one of them, they won't be marked as "read" or as "deleted".

2) In the firefox toolbar Bamboo feed reader shows its icon (that's OK) and the number of unread feeds (I wish that would be customizable). The number of unread feeds stays the same even if all feeds are read.

3) Clicking on a feed opens the link in an existing tab. That may even be a tab in another firefox window. Sucks.

Otherwise: A very good plugin.

This review is for a previous version of the add-on (1.5.1.1-signed). 

The new version 1.7 can be used in any window without problem.
I invite you to try it and make a new review if your opinion has changed.