They dont set on the ground when using. There are held up slightly ( at least the ones ive used in the past. I think the rear pull style do run on a roller as i recall). so as not to totally engage the dirt and rocks completely. Its a large weight off to the side. You have to be careful not to drive off into the ditch even a little bit with a light tractor. Our highway district uses one with a large counterweight on other side due to tipping issues.
Id love to get one myself, but ive spent way too much money in the last 2 years. My tractor is pretty heavy, so i dont think id have issues, but its not high on my priority list. I just finally got a
grapple this year. Man i love that thing. Saves me so much time.