I have had three stump grinders in the eight years I have been retired. My favorite is my current Carlton SP7015, 66HP turbo diesel, 4 wheel drive, push blade, razor wheel, and remote. I bought this grinder in November 2012. The price then was $53,000 for that setup. I checked very recently and the same setup is $65,000. I absolutely love this machine in spite of some quality control issues that Carlton totally missed and cost me to repair but that is a different story. With a higher HP machine you can make a ton of money very fast if you market yourself right and you live in, or near, a large metropolitan area. My grinder has wheels. There has never been a job I couldn't get to but I do hate taking the wheels off to go through narrow gates. I have been stuck once (even with 4 WD) on a horse ranch and the ranch hand had to give me a shove with his tractor.