I used to use this extension, but it now has horrible performance on Firefox. It sucks up all resources and freezes the entire browser when a page is loading. You know how normally when a page is loading, you can still click on other tabs and the browser will respond? Not with Simplify! I've seen faster browsing on a Core 2 Duo.

I know this extension used to work well. I think something changed in a recent update. Hopefully this is fixed soon, but I know firefox users are usually not a priority demographic.