What I like: it works! It took at least 5 applications for me to see a difference (I have dark hair). But then, it really started! It brightens my already there highlights and turns my dark brown hair a nice auburn color.
What I don't like: I dislike the texture of my hair after I use this. So, I'm putting it on at night, letting it dry naturally. Wash as usual in the morning. This seems to work best for me.