We all like it now. My girls are both very visual, and the book is loaded with word problems and bar models to help solve them. Those were new for my 6th grader, but now she has the hang of them and how they work. She went from taking an hour to do a test (all the way from 3rd grade) to 20 minutes for the last two. It's been a serious improvement in her confidence and enjoyment of math.
I got math in focus for kindergarten. I've heard great things about it :)
Quoting TidewaterClan: Both of my girls (3rd & 6th grades) are doing extremely well with Math in Focus. It's a mastery based program, so goes into depth in each topic before moving on to the next.
I always look at http://cathyduffyreviews.com/ for reviews too. She has a great section on math (among other subjects!).