We've used Horizon's Math for five years and it is, by far, the best math curriculum available. I have two girls that can sometimes get pretty frustrated with the more difficult lessons, but with Horizon's that frustration is usually short-lived. It will introduce a difficult activity and then go back to easier tasks that build back up to the more difficult ones. It's bright and colorful pages keep their interest piqued. Since we started Horizon's, my girls stay 2-3 grade levels ahead in math!!
I have used Horizons K-8. It has always been a bit fater paced than the "average" math curriculum in ALL their subjects. I would not recomend this for any student who has not completed Horizons grade 7 or is a strong math student. It moves just as quickly as any other Horizons. I found the classwork to be far tougher than the tests. I appreciated the practical application aspects. It does well in covering the topics and teaching application. There is not a ton of practice on each concept, but more than enough for a GOOD math student that would get bored the extreme repetition. I am more than happy with it. I have bought Grade 8 and can't wait for grade 9.
I have used Horizons for K-6th and was so excited to see they added Pre-Algebra. However, it has not worked out well at all for us. It is very fast paced but gives very little practice of new concepts. We also have found that at times a new concept is just introduced and in the first few problems they give the student, there is an exception to the rule or a very complex problem. The student does not even get a chance to learn the basics before complexities are given to them. My son who loves math and has alway done very well now is very discouraged and hates math. I have stopped the program half way through the year and will not continue with Horizons after 6th grade. Hopefully they can improve this product in the future to be up to par with their K-6th math.
I have used Horizons for K-2 and 5 and always felt it was a complete and advanced program. After competing Horizons 2, my older daughter was a year ahead in math when she entered school. With my himeschooled younger child, we switched to Saxon 7/6 for 5th grade and my daughter really balked at the boring black and white layout and repetitiveness. I think Saxon is a great program, but my daughter really likes color. It seems crazy to switch for this reason, but if the layout is unappealing, it can be very difficult to persevere. When I saw Horizon had Pre-Algebra, I jumped on it. We have been doing it for twenty days and overall we are happy. I would say that it moves quite quickly and does not offer as much practice as Saxon. It also does not offer the complete explanations in the Teachers Guide offered by Saxon, but it does cover all the same material. Most importantly, my daughter is working through it happily and is doing well on the tests. I always work through the problems first to be sure I can explain them well. The TM could definitely offer more detail. If you are not a math person, this curriculum may not be for you.
We love the stories of real life people who use math in their work. The word problems are engaging, although there could be more. I do think this curriculum will well prepare a student for Algebra. I have been comparing the Scope and Sequence to a public school math book and it definitely lines up. I love that we can reasonably complete one lesson per day. I will definitely consider horizons Algebra I next year.
I used Horizons for 3d, 4th, 5th, and 6th with no complaints. But, this book was a disappointment. I really agonized whether to switch to Saxon for pre-algebra but went with Horizons b/c it has color (lol) and my daughter loves that. The pre-algebra book is very fast paced (there is a new topic every day), but there are not enough practice problems and worksheets. I think they tried to cram too much into this book. We're trying a "real" text for algebra next year (rather than a homeschool text).