Our GATE school uses EM. The entire district adopted it about 5 years ago and the GATE school continued using Saxon math until a very vocal group of parents wondered why EM was good enough for their kids but not the GATE kids. So, they moved our school over to EM. It hasn't been horrible but they do supplement with Challenge Math and each child in this program is at least one grade level ahead at math.
I am hoping they will pick a new program when the 7 year contract is up and that my dd will only have 2 years of this program. I don't fully trust it but happily I do fully trust her teacher.
