As a kid I raced motocross, we had three bikes, all the same. One my brother raced, one I raced and one we had as an open bike we'd race in the open class. We also used the open bike as an emergency parts bike if need be.
We'd sell all three at the end of the season and do the same thing the next season.
Only way we knew for sure that we'd have exactly what we need no matter what failed on race day.
No matter what manufacturer you go with you'll find some parts imediately availabe and some not and no way to predict which will be which.
At the end of the day you'll find no material difference between Kioti and any of the other major brands.
PS, my last tractor was a Kubota B6000e, I had two of them so that I'd know I'd have a running machine just about no matter what.
My point was, if you want zero down time get a second machine, nothing more nothing less.
Joel