The fieldstar is acurate if you calibrate it correctly. You need to do a zero point calibration, which zeroes out the vibrations of the machine, and then do an automated yield calibration. You will want to do the yield calibration 2 or more times, depending on the accuracy you want. Fieldstar is also pretty easy to use, and each new software version gets even easier. Make sure you have the latest software version. Version 4.31. The software updates are provided by AGCO free of charge.