We had the JD 950 which is entirely built by Yanmar (as is the 850), it just has the green badges on it. We put 5500 brutal hours on it and the only problem we had with it was that the keeper pin on the diff spider gears shore of and banged stuff up pretty good. Engine still started and ran like a top, didn't use a drop of oil in the 100 hour change interval. We have a Yanmar 5500W Diesel genset which starts on the first pull at -25C (smokes like heck, as any diesel does at that temp though). both are good on fuel, I like the luggability of the Yanmar tractor, it was only 28 drawbar HP but was just about as fast going up the hills with a bale wagon of hay as our Massey 165 (55 HP) and our IH 685 (70 HP). For a small tractor it was really good. The downfalls of it was the straight cut gears in the tranny, they took a lot of skill to not grind, and it was impossible to not grind coming *out* of second (2nd gear touches the reverse idler on the way out), and they don't have much traction. The other gripe we had about the JD 950 was that it had no power steering and poor traction for pulling field implements.
As I'm parked outside a gas station now, I will tell you the price of Diesel here... 1.43/L. (darned close to $5.50/gal)
This is a much more heavy duty tractor, and I think it would be a good machine
I think I might get myself a motorcycle again! Maybe I'll even have to go for a moped