After reading these reviews, you will be able to decide for yourself which rotor to purchase.
Personally I own a NTE U105, NTE U106 and Antennacraft TDP2. All are more reliable than the Channel Master 9521 and can drive a large antenna just as long as you keep the mast to a foot in length in the rotor itself.
http://www.amazon.com/PCT-Internatio...DateDescending
http://www.amazon.com/ANTENNACRAFT-R...nnacraft+tdp-2
http://www.amazon.com/U-106-Antenna-...words=nte+u106
http://www.solidsignal.com/pview.asp...07&tab=reviews
http://www.solidsignal.com/pview.asp...A)&tab=reviews