I would second SWMan's comment about trusting this brand over any other for high hour machines.
We ran two MT845B's in the early 2000's.
We bought both of them from a big farm down in Texas. They were pretty decent. The most trouble was with little things like the fan blower for the cab air.
Actually, when I think back to the hot days that I ran it with no AC, it didn't seem small at the time, lol.
Anyway, we just bought another Challenger, after having other brands of tracked machines.
We got a new (first new tractor in 14 years) MT 875E.
Oh the torque. We have two hundred hours on it so far and love it.
Hopefully I can say the same thing in another 5000 hours.
After running it this little bit of time, I can't see why not.
"A farmer is a man outstanding in his field."