CTY is less forgiving that EPGY for "self-pacing". My kids have found it harder to keep up with the pace of CTY when they can only spend 20-30 minutes a day (or every other day). EPGY suggests 20 minutes a day for that age which worked well for us (CTY was more like an hour). My son has loved EPGY and it has been a perfect "extra" for him. That said, EPGY is rather drill like and practicing--harder and more interactive than IXL, but same vein. Dreambox is more video game-like, but I am not as convinced my kids learned a whole lot from it (they had to do it in school). Hope that helps!
