My son's school uses Go Math! and they follow it to the letter, going through each lesson exactly as presented in the materials. He's in second grade now and has been using this program since kindergarten, so I know it well. I've also purchased the supplementary Student Practice books for each level up through 4th grade, so I've got a good sense of the scope and sequence of the program and how concepts are taught. That said, math is not and has never been a strength of mine -- so I don't have the insight that a "mathy" person might. My thoughts:
Fewer topics are covered in the early years than in some other programs, though they eventually get to everything if you go through the whole program. If you read their materials, you learn that this is deliberate; they specifically aim to cover less but to make sure the kids really understand the math. It's a very conceptual program with a strong focus on ensuring that kids can process the reasoning behind what they are doing. Students are regularly asked to explain their understanding, which gets quite tedious and frustrating but also helps the teacher (and parent) see where a child lacks understanding. There are many word problems and lots of applied math, which is good. Go Math! is obsessed with ten frames in the early grades, and I wish they would represent numbers in different ways (number bonds, number lines, etc.). On the other hand, all the ten frame work does ensure that students have a firm base 10 mentality moving forward, which is good. Go Math! also builds spiral review into the homework assignments (if your child's teacher uses them). This has been great, as it has prevented my son from forgetting previously learned concepts and skills.
Like someone else said, I have sometimes found the assessments to be more challenging than the daily homework. I have not found the program in general to be too easy, but then again, I am not "mathy" (and neither is my son). I'd say the level of challenge is just about right.
Hope this helps.
Edited by lilajoy, 21 April 2017 - 02:40 PM.