We were up north of Eagle River this weekend with the family. One of my relatives has a Doo 900. The eco mode is an incredible idea - my 9 year old has outgrown the 120 they have up there but was able to ride all around a small lake for 3 days on a Doo 900 because the eco mode keeps the acceleration and the top end down to something he could manage. Without that there's no way he could be on full size sled. That's a probably a feature most don't care about but it really made the sled youth-friendly. They should all have something like that...