Starting a new math curriculum on Monday

We have been using MEP (Mathematics Enhancement Programme) which covers grades 1-6. Don't get me wrong. It is an exceptional program and (best of all) free and we WILL continue to use it, but I just felt like we needed something more. After lots of research and opinion gathering, I purchased Math Mammoth today. $72 for the Lightblue Series which is a full mathematics curriculum for grades 1-4. It's designed to be self-teaching and seems to be pretty easy to follow. I'll keep you updated on how it works for us.