I have a new 9870 and 635D, The 635D is the first draper head in our area so I really don't know anything about Draper heads. It feeds really well and we have been cutting alot of that junk 8 bu. wheat with 60bu. straw right on the ground. Only problem with head is it cuts lower on left side in auto. mode, it was calibrated at dealership but we may have to redo it. 9870 had a brake sensor bad from the word go but that is fixed now. I had dealer install 4 wheel drive of off 6o series machine and we have had some issues with this, It is not engaging and disengaging properly. I don't really need it in a desert anyway. Machine seems really quiet, new monitor is nice and easy to operate, Lots of power, diesel is around 1-1.25 gal. per acre depending on straw thickness. Wheat is all poor unless it is on top of Hill where the freezes did not get it most wheat won't be harvested.