Rated 4 out of 5 stars
All page loading, and even scrolling previously opened pages, hesitates for a second. Some clicked actions in Firefox do the same thing. It all returns to normal when Greasefire is Disabled. We need a checkbox to disable Greasefire scanning until we're ready to use it. Restarting to Enable, then again to Disable sucks.
I really love this addon and am excited that both GM and this still work so well with Firefox 12. However, I'll be running with it Disabled mostly.