I have a 4610 and love it so far. I'll never have a tractor without hst after using one. I really wish it had the jd brake setup on the left side, I miss this from the other tractors I have used.
I was dead set on buying a jd 4520 or 4720 (used) which my neighbor has and i was able to test out a bit, i really liked it. when i asked his opinion he said that and he has bought nothing but brand new deeres his whole life, and that each one he bought he has had more problems with he was saying that he has about 2000 hours on it at the time. His opinion was that he wouldn't buy another one but most likely this will be his last tractor anyways. This was just my neighbors opinion on his experience and keep in mind he has never owned anything but Deere.
I really think a lot of what makes one tractor good or bad is how you run the equipment. I'm not brand loyal and, in fact, just bought a John Deere backhoe. However that isn't anything like the smaller tractors anyhow. I will still consider Deere or other tractor when I upgrade though even though I really do respect my neighbors opinion, however, I'm sure there are just as many kubota owners that say the same thing.
They are both great manufacturers and kubota isn't better than Deere or Deere isn't better than kubota, it's all personal preference, just like the ford vs chevy debate.