Rated 5 out of 5 stars

Using Babylon Word Search on a daily basis for a year and and a half now, and it does its job incredibly well. On Firefox 3.X - 8.0 Linux & Windows. Whenever doubt on a word, ALT+Y and the doubt's gone :-)
Oh, and never ever took over my search preferences, nor a single issue to remove it.

This review is for a previous version of the add-on (1.2.1).  This user has other reviews of this add-on.