First off, I have to stress one detail. I have only done a small amount of work on dozers- and that was on big CATs My knowledge of these smaller machines comes primarily from research, and thus no hands-on experience... yet. I'll be pulling everything from the tracks to the reverser before I can run mine.
The steering system description on the case machine, that sounds wrong to me. The only double power delivery system I was aware of is the big CAT hydraulic over mechanical on the high track models, but I don't speak with authority on that matter either. But keep in mind I am *only* referring to the Case 350. But with diff steer machines, when you brake one side it doubles the speed on the other side due to the diff gears walking.
Accessing the steering on the Deere's can be a bummer, but from what I can tell the hard part is in the handling of big parts. On the 350's you have to pull the finals to get to the clutch/brake. The 350/350b use dry, but everything later (350c, 350d, 400 etc) use wet clutch brake systems which last a LONG LONG time. Also, the parts interchangeability is such that the metallic wet discs can be swapped into the dry clutch models. They are still run dry, but here's why it's worth considering:
The fiber steering clutches don't like to get moist. They swell and lock up. Once locked (from sitting for a long time usually) it can be very difficult to free them up- sometimes teardown is required. But this failure won't happen with the metallic clutches. Adjustment is a big bummer, I'll also give you that. Newer hydraulic self adjusting systems help a lot with that, but older 350's are all mechanical linkages.
Most dozer owners are not the average shade tree mechanic, but that type of owner is MUCH more common with these smaller machines. The problems come in handling the heavy parts (proper rigging) and the initial internal adjustments of the clutch. Without the little depth tool it is effectively IMPOSSIBLE to adjust correctly, and the finals have to come back off to correct the screwup. I still think the average shade tree can do fine IF he/she does the necessary homework. My opinion is that the bulk of problems come when they do not.