RSM was a bit too intense for our kids, it was great in a sense that the kids could practice specific weaknesses they had (from the assessment that they took) but in the end they didn't seem to strive from it. Kumon was a bit too repetitive for them, I've also done Kumon when I was a kid years back so I could also be biased. IXL is also useful but we also found it repetitive. So far we've really enjoyed Beestar, but then again, each kid is different so it really depends on their learning style!