Just a note that IXL can exacerbate perfectionist tendenciea. Their smart scoring drove my daughter to distraction. Even when she knew the material, the thought that one wrong answer at the very end would drop her score 10 points or more made her nervous enough to make errors.
Your mileage will obviously vary.
This happened with my kids as well and I was worried they would give up.
We did a trial of dreambox last year (maybe just DS? I don't remember) and I thought the version for his age was kind of dumb, but now that he's on more advanced grade I like it more. It has some glitches and is not perfect, but one thing I like about it is that is very visual, and lays all the concepts out in pictures. It continually assesses to find the right level for a kid, though I made the mistake of putting DS in third grade level. Some of it is fine but I had to go through and do all multiplication and division sections on my own to get it past that, so he wouldn't have to suffer through it endlessly. The pace can be kind of slow for gifted kids, even if they pass material in the pre-testing. But it has been more successful with DS than any of the other online programs. We will probably go through Khan Academy just as a review or to cover missed or unclear topics.
