It is surprising how much my girls are enjoying it (they are in 5th and 7th) and we have done very informal science up to this point. I think 6th would be a great age for Rainbow. I'm on the fence about continuing with the second year with my then 8th grader, I would really like to see her using a "real" textbook to get used to the rigors of hs science so by then we might just switch over to BJU. I sometimes wish the readings were longer or a little more fleshed out, but Apologia General was the opposite and they seem to be retaining better with short snippets rather than long monologues ala Apologia. Hope this helps