At the upper end of John Deere’s 6020 four-pot line, buyers get a choice of 81kW/110hp 6420 or 88kW/120hp 6420 S, the extra 7kW/10hp costing in the region of £1,020. This month’s profi tractor test digs a little deeper into the ‘S’ factor, at the same time taking a detailed and closer look at the noteworthy features on the new 6020-series range