Depends. Go read Pete's post two clicks down in the JD vs 570r thread, same principal applies. If your conditions are suitable for a rotor, then the bi-rotor is probably overkill. If you want a machine that will perform best in heavy crops, weeds, tough conditions, then you should look at something besides a single rotor. Comparing a rotor with a bi-rotor is like comparing apples and oranges. The only thing they have in common is they are both combines (or fruits in the apple and oranage's case).