I guess I'll have to defend the Columbia rear ends. The Columbia under my '36, a '47-48 unit, hooked to the original '36 Ford 3.78 center section has been in operation in my car for over 50k. The only problem I have ever had with it was a spacer washer failed causing the right axle to seize. That was kind of scarey because I was doing over 65 mph when the wheel locked up.
My car has had a Columbia under it since it was new, the car has 140k on the odometer. I replaced the '36 Columbia with the later model because there were things I did not like about the earlier units.
My engine is a well built 59AB engine, when I was younger I would drag race the car on a regular basis, never had any issues with the Columbia. I think the problem with the Columbia's for many people is they don't know how or when to shift them, the same is true of trucks with 2 speed rear ends. A two speed axle should never be shifted on the down hill, nor should they be shifted into low range while the vehicle has been allowed to roll with the clutch depressed.
Down shifts are made by momentarily releasing the gas peddle, while momentarily depressing the clutch. Releasing the throttle increases the vacuum, depressing the clutch takes the pressure off of the gears, thereby allowing the vacuum shift piston to shift the gears in the Columbia..
The late model vacuum/electric shift controls work pretty slick.