I have both the 6-8753 "Tuscan" and the 6-8150 Green MPC era GG-1's. The 6-8753 does have the dreaded nylon gears which have held up well. Both locomotives are solid runners and, perhaps for nostalgic reasons, are still equipped with their original E-units which have been trouble free.
Maybe I'm color blind, bout I have no issue with the Tuscan color: