That's the best thing that can be said for a pull behind. Very little down time. Almost nothing to break. I never did anything to my 502 but a clutch and a fuel pump. Hydraulic drive brings a whole world of new problems. But I don't think I could ever leave to versatility and go back to a pull behind.Vermeer is the only company that seems to understand that chip containment is important...however; that being said why develope a self propelled stumper grinder line that involves the 2 most expensive ways of transmitting power to the working end? Follow that up with "oopsey! Out of motors and no new designs ready!" Good work from the original stump cutter maker. Too many irons in the fire if you ask me.