To me the question is wrong. Now I operate a 4520 which is largely American. But more important is who designed it and set the standards. You can build anything anywhere so what matters is the specs.
One John Deere fellow pointed out to me that all John Deeres are designed by John Deere Engineers and all factories that build Deere material are held to high standards of John Deere...period. So really a moot point.
Kubota, which I used to own, a 3710, was a great tractor, built in Japan mostly and it reflected their culture. I am a bit big so I found there stuff a bit small and occassionally a bit toy like...but a great tractor. There problem is their monetary policies which lead to realatively high costs for what you get.
I get a bit tickled when people try to make the color green expensive. I got my 4520 at a substantially lower price than the comparably sized Kubota...and that being while I owned a Kubota