I have an SK650 and its the best investment I ever made in equipment. I looked at the 850 as well, but I was put off by the lower horsepower which is about 5 less than the 650, and the fact that I could not imagine ever changing a hydraulic hose on it. The 650 is bad enough for space. I went instead with the SK650 and a bradco backhoe attachment and it has been really good. I put a 200 foot septic field and two big tanks in with it in a little back yard not long ago.