We use EPGY as the main curriculum and supplement with Singapore. EPGY is good for getting the basics down and requires less adult time per unit kid time. Then we use Singapore for the things that it does well, like the mental math strategies and the word problems.
We've also just started also using the art of problem solving Prealgebra book and it's quite good.
AOPS is a step up from most presentations of the same material, so if you have accelerated to the point where math is challenging, you might find that it is worth going through prealgebra once at "EPGY-level" and then going back through it at "AOPS-level"
