We used PACEs for a half year to review fractions. PACES go over math in great detail, if you have a slow learner, this is great. There is lots of practice. If you have a fast learner, you can move fast through each math pace. You do not want the child to become bored, yet you want to make sure they are grasping the concept. They do have a placement test here which is online so you can find out where exactly to place your child in their math program.
You might also want to look at LIFEPAC to compare the two. Lifepac is having a 20% off April Sale. There aren't too many days left in April so if you decide on Lifepac, you have a few days left to get in on their sale. I have used Lifepac history and science but have not used the math. They do have a placement test online, which you can find at LIFEPAC website. Just don't forget.......
All Horizons Math and Language Arts Products Are 20% Off During April!
One more thing before I go, you can always order a book from each company and try them out...as you can order them individually. That way you can compare the two side by side.
Happy Math Curriculum hunting!