As far as I can tell Isla is simpler and probably better for younger children than LOGO. In my opinion LOGO is actually harder to learn than Python or Ruby for children (at least in my experience from the couple of children I was trying to teach)
Really? I remember picking up LOGO in Kindergarten. Can't even imagine working with a real language back then. How old were these children and how did you go about teaching them?
They were 6 and 10, python seemed easier for them to pick up because they had more control AKA I think the turtle and what not confused them. It was much easier for them to name everything themselves and do what they wanted.