Traded in my 825i for the 855D because I wanted the factory power steering and the lower fuel consumption of the diesel (I had an 850D and knew it sipped fuel compared to the gas engine). Some feedback on the differences;

1.) I had installed WickedBilt Power Steering on the 825i and wasn't that happy with the performance with the Boss Snow Plow on - it gave little assist and I feared the electric motor was undersized for the tie rod loads generated by the plow's weight. The 855D's power steering is outstanding!! It is clearly engineered for the weight of the plow and beyond - seemless operation. This was worth the trade alone

2.) 855D seems to have a higher trim height (or standing height) - seems like it is 3 or 4 inches higher - I don't know if this is because my 825i's springs had settled over the last 2 years or not

3.) Acceleration and throttle response was much better on the 825i - I know there is a big HP difference but thought the diesel might provide more torque for quick launches - it is not geared that way and is not a lively drive

4.) All of the driveline noises from the 825i are gone!!!! Finally this machine sounds like a very high quality piece!

5.) The lights that mount on the front brush guard are redesigned to be larger and they are made by Hella - haven't tried them yet for performance but the come with really ugly covers that are white - had to discard them immediately

Overall I am very happy with the upgrade. The 855D feels like John Deere is making continuous improvements on Gators!!!