Try cramming 40 feet of high-yielding green damp wheat straw through your combine while chopping the straw, unloading on the go, in the mud, up hill....both ways. That's why they offer 5 different sizes....few will be interested in a S690. But there are some out there who will be, especially in Canada and Europe. Those are the markets that machine is really designed for. I rode in a 9870 this summer with taking 40 feet of down, green straw, and it made that machine work pretty good, and it's easy to image conditions much worse than that day, so some will find the option of that power welcome. But it's not like it's way, over the top more powerful...Lexion is only a few poinies behind. And whats the difference between their class 9 and 10?