I thank you all for your responses. To update, we stopped ixl after our first month. The perfectionist in him couldn't take it. We dabbled in Khan for a bit and then started EGPY at the very end of June. He grew frustrated after about a week, at which point I realized that he wasn't on the gifted setting. We fixed that and he is enjoying it quite a bit, even though I find it pretty dry.

http://www.my-little-poppies.com