We really are using it! Besides the notebooking pages there are sets for timelines (book of centuries!), and in some of the sets you find coloring pages too. Some of the sets with coloring pages include birds and flowers sets, sports, transportation, and animals. I plan to use the sports notebooking pages in July/Aug as we watch the Olympics, so my littlest ones can use the coloring pages while older ones will draw their own pictures and use the notebooking pages with spaces for writing and drawing.
There is a demo video now for the new web application that they're releasing next month that allows you to create your own notebook pages. It is included in the membership and this will be great too. You can use any photo, clipart, or pictures in the templates, kids can type right into the templates instead of writing by hand, or you can create a page from scratch adding lines and boxes or pictures anywhere you wish. I'll be making a set of physics notebook pages to go with Christian Kids Explore Physics for my kids science next year, and a set of pages for the people, places, and events of our church history to go with the history curriculum I'm in the process of writing right now.
And when you really break down the expense of the sale price ($56.21) over being able to use the notebook pages for all your children for all their years of schooling (for me that's 7x12!) I'm paying pennies per child. Being able to have access to these files forever is really appealing, I don't have to renew my membership every year for that.
If you have any other questions be sure to just ask me!
Oh, and I AM and affiliate now, having used the products a bit and discovered I really love them it was worth it to me to promote them. My affiliate link is: http://notebookingpages.com/dap/a/?a=5853 so if you do decide their product is right for you I'd love it if you click through my link when you're ready to make your purchase!