With my oldest child, I never switched curricula unless it wasn't working. Why fix something if it ain't broke, right? My second child is thriving with Rightstart. Math is his favorite subject, and I think a lot of it is because of how Rightstart is designed. However, it's pretty parent intensive and expensive. He's also mathy like his sister, already working on level C though he just started first grade. I already have all the Beast levels published, and I like the rigor of Art of Problem Solving. I'm really struggling with dropping $110 to get level D for him, when we already have a great math curriculum. He's been reading the Beast Academy guides, but he insists that he wants to stick with Rightstart Math. Any advice on selling him on Beast? Or should I just suck it up?