DS used it for half of last year (after he was accelerated mid-year). He only brought home the textbook for a few weeks and then started doing homework off an online program (and I wasn't looking at it), so I can't say much about the curriculum, other than I didn't see anything glaringly wrong with it and it taught concepts a lot better than the curriculum DD was using at a different school (Holt). I felt like with Holt, she was just learning to do calculations and didn't actually understand the math. Connected Math had a lot of word problems, for instance in the fraction unit. DS also went from saying he hated math to "math is my favorite subject". He said that the math class was really "fun". I think if he had been placed in Holt he would have continued saying he hates math, even if it was the right level. My understanding is that a lot of in-class manipulatives and some group work are also involved with Connected math.
