There are significant differences in these three machines - I like old jap tractors. First, I would recommend the JD650 for a few reasons: parts avail will be best, easy to find mechanic, and the Yanmar (company that actually built this tractor) build quality is top notch.
The MF1010 is a nice cute tractor, made by Hinomoto for Massey. The catch is that Hinomoto is long out of business, and parts for these machines are getting scarce. Not impossible, but scarce. It is also much harder to fit a loader to a 1010/20/30 than the 650 deere. That being said, if the MF is in far nicer condition, or much cheaper- it might be worth further research. Before buying, check around to make certain a local dealer/shop will work on it.
Lastly, the Kubota 185 is a much older design than the other two tractors. It is also a bit bigger, higher standing. Both the 650 and 1010 are almost sub-compacts, low stance that is good for mowing and stability. the 185 will sit higher and narrow, showing it's rice farming heritage. The 185 is also a 2cyl - if my memory serves, and will run rougher and louder. Last, the Kubota 175 was a two cycle diesel - I dont remember if the 185 was as well. Could be dead wrong on that....anyhow, it is a design that dates to the early 70s, so I would rank it last. In its defense, it is a bullet proof tractor, and my Kubota dealer still provides support for the old girls - maybe others do as well.
