Attention math and science majors: is Saxon Math acceptable for gifted students?

After purchasing Saxon 1/2 (pre algebra) for my son, I have found several websites that contain criticism from the math community regarding Saxon. My kid is 9 years old and very gifted in math. We have used Singapore for a few years and he has completed all of the books and is finishing up 6th grade. I purchased Saxon after it was highly praised by some erudite friends of mine, and now am regretting it. These friends were scholars of the liberal arts.... Should I send it back? Can anyone recommend something better, that lends itself to acceleration? My son's joyful obsession with math depends on it.