Rated 2 out of 5 stars

I think it's easier to use keywords. Instead of clicking "videos" and write "metallica" for example, you can just write "y metallica" for youtube after setting "y" for youtube.
Unnecessary I think. Maybe good for lazy people who don't want to set keywords for sites.

This review is for a previous version of the add-on (1). 

The add-on works with just the keyboard as well. You can press ctrl-T to open a new tab then type "v" and press [tab] to start searching for videos. So very similar to keywords.