I just took a class with Karen at the MQX show and bought this book as well as the Elemental quilting book. I love her motifs, or as she calls them, elements, in both books. And the video is great, they make it look so easy, don't they?
I did get a crescent ruler at the show as well but not Rhonda's, I got the Radical Ruler by Dusty Farrell. I have not yet had an opportunity to try it. I plan on drafting on paper first. Can't wait to start playing with both Karen's designs and the curved cross hatching.