Pretty easy to use for programming my truck, and can't argue with the outstanding results. Set it for the mileage mode and gained 1.5mpg (3 tank avg) and still have plenty of power for daily driving. Very easy to change mode when I needed to tow, then return. Also used it to correct my speedo for larger tires and diff; that was a little trickier. Using GPS and cross-checking with mile markers, it was still a little off (6%, down from 9%)). Had to adjust the settings I inputed to get right on (with-in 3%).