Rated 5 out of 5 stars

Great Addon! I used "Update Scanner" a long time (which is good, too), but SideDelta is much better. The only negative is that it doesn't work with the "javascript.options.jit.chrome" enabled in "about:config". If it scans a page my Firefox freezes for about 10-30 seconds. See here: https://wiki.mozilla.org/JavaScript:TraceMonkey

This review is for a previous version of the add-on (0.11.1). 

This problem with "javascript.options.jit.chrome" enabled is caused by Firefox bug 502058 which should be fixed in one of the next Firefox releases.