Rated 3 out of 5 stars
It was excellent for 3.6 that I still used (mostly because I hated FF 4 UI [but then saw 26] and more importantly, last compilations of SwiftFox (CPU optimized (AMD/Intel, x86/x64) were of 3.6 series - and it worked.
But SOMEONE fork it or AUTHOR upgrade it. I'm now trying with simple edit of install.rdf with MaxVersion set to 27.*.*
Of course, if no official help, I *can* have same functionality with keysnail extension - the code is there (builtin) and even hides *title bar*.
But I guess 4 stars for it working on version it was made for. Only 3 if there had been any other serious lack (well, you should be able to set the hotkey with ANY modifier-combo and ANY key - so three stars. Fix these and you have 5 from me. With 800x600 (Asus EeePc netbook) it was superior.