Re: WHAT TO BUY
The Deere gps unit is not the best just based on accuracy. The Deere system looks like it was part of the equipment and designed to be an integral part right from the design stage. It fits in so nicely, the resume buttons are in a perfect spot and everything just feels right with it. A trimble system just looks and feels like an add on after thought. And yes I do own 2 trimble units.
Fuel usage. The 8010 is what 440 hp? and the 9760 is 340 hp, so it stands to reason that the 8010 will burn more fuel. A 9860 also burns way more fuel than a 9760 and the 9870 is 440hp so it will probably burn about the same amount of fuel as an 8010.
Don't know if you bale straw or not, but an 8010 will let you drop the straw and still spread the chaff, which a deere will not.
Both are good machines, with lots of dealers and parts. Resale will be good on both. I would also second the motion to buy a Macdon header no matter what color combine.