Not a lot of them out there on surplus. Relative to other MV not a lot of them made. Parts are hit and miss on availability. When I got mine it was missing an alternator belt pulley and bracket, well this particular C12 engine arrangement requires a special order from Cat on the bracket, which took two months. I figured that's why it was missing. I'm finding that some electrical components are small qty, or one-off production for this vehicle and hard to find. I haven't seen anyone post copies or a link to an actual parts manual.
Ours is low miles and low hours, so we haven't had any drivetrain issues yet, so can't speak to that maintenance. There's probably never going to be an abundance of parts for these things like the older 5 tons, therefore, it's going to be more of a hassle to maintain. That's my 2 cents.