I love this extension. In addition to the features advertised, it's great for people with disabilities. I was a lousy typist before surgery on my right hand, and now it's worse. I make many mistakes, and simply chasing & clicking on red-lined words is difficult. Now all of my errors are collected in a single location and fixing them is a breeze. Definitely worth 5 stars.

[edit]: I just typed "tried" as "tired", an error regular spell checkers wouldn't catch. This one did. How do I give it 6 stars?