We use it and love it. It has a spiraling curriculum, so what you learn on page one you will see again, and again, and again. This makes sure your child does not forget it. It also moves very nicely imo. We do both math 1 for dd and math 5/6 for ds.
“Then the Grinch thought of something he hadn't before! What if Christmas, he thought, doesn't come from a store. What if Christmas...perhaps...means a little bit more!”
― Dr. Seuss, How the Grinch Stole Christmas!