We have a set of grip tracs, they worked very well this harvest. Road speed seems to be cut in half. As far as power goes, they were much better than tires because they didn't sink. With tires on we were running out of power with our CX880 but once we put the tracks on we never ran out of power. We felt that rear wheel assist wasn't necessary, but bigger tires on the back would have helped with the ruts. We have never seen it as wet as this year, we had over 20 inches of rain during harvest. Our tracks are a little over 1 year old, if anyone is interested in them we will be trying to sell them. Tracks are very easy to install and fit most combines.