Depends on your requirements, I'd say.. Like BTI said, if you need HST or a mid mower, go Kubota because Kioti doesn't offer that (though they will offer HST in the fall I hear). Otherwise, keep an open mind.. I was leaning towards JD or Kubota, but now I am pretty sure I'll be getting a Kioti DK40.. Kubota and JD don't seem to make a comparable tractor for the money, or for any amount of money.. The Kioti's outweigh the others, and the DK40's front end loader can lift 2100-2500 lbs depending on which FEL you get. Outstanding..
Just MHO.. I'm currently borrowing a JD 4200 HST and it's a great tractor. But when I plunk down my own cash, I want the most bang for my buck.