Rated 4 out of 5 stars

Great add-on! The basic idea of limiting the number of tabs that can be open should be a feature of Firefox itself, IMO. That said, like others have suggested, it would be great if, when a user tries to open one too many tabs, that tab simply wouldn't open. I wouldn't want to have a tab that I'm still using close, just because it's the oldest. From there, having both options when opening a new tab - closing the oldest tab or not opening the new tab - might be nice, though I'd only need the latter option (at least at the moment). The option of a short beep or a small pop-up when the tab limit is hit would also be a good thing. (Having both options cover different accessibility issues.)

This review is for a previous version of the add-on (2.6).