Great idea, terrible interface Rated 4 out of 5 stars
Can't say I'm any fond of the rainbow colors, but this is a very great idea for an addon. The "Highlight" option hardly works though. So I just use the "Book Text Mark" option and just drag the rainbow bar to the area I want.
Another problem is that the bookmarks menu for Book Text Mark doesn't show my lists of saved book text marks. But since I have it in my context menu, that's alright.
The incredible usefulness of this addon deserves a high grade, despite all of the flaws I think it has. If anything gets updated or fixed, I'm hoping it will be those horrible rainbow colors.