I did do the Island level of MCT with Harpo when he was 6, and it worked really well. Just as a heads-up, though, there was a fairly significant jump in difficulty level between Island and Town (especially the vocabulary book); it was still fine, but it took us a good bit longer to do the second series
I think there are a lot of ways to approach MCT. My 5 year old *LOVES* the Island level books, listened intently all year, and participated in our discussions. She took a good amount away from it. But she wasn't really able to do much of the actual writing exercises, so we're going to come back to it later. Both my kids physically write probably close to grade level. My 3rd grader did a lot more writing/application than the suggested exercises in the book so he took it to a deeper level (much of his longer writing he typed). I think this is very much the beauty of the curriculum is it's open-endedness. I really don't get any kick backs from MCT, but I think it is brilliantly designed.
