Like most things in life, there are auto boxes and there are auto boxes.
The Asian stuff is generally very reliable but not very clever and they feel rubbish compared to a decent auto box.
I believe the ranger 3.2 has a box which is fords own unit. Probably the same as fitted to their cars in the US. It is a bit clunky, not very clever but should be be good for towing and off road. In fact of all the ranger issues I know people have had I've never heard of the box being an issue.
A lot of companies use ZF. Ive got one in a Land rover, they are in Audi and probably loads of others. They are superb. Smooth, fast, great when towing.
Ive got another car from 2007 with a Getrag auto box and its nothing like the ZF in the newer land rover. Its smooth enough but takes an age to shift in comparison, however it handles a lot of power and torque very well and is apparently good for loads of miles. It will also locks the torque converter in 1st immediately so it launches better than a manual.
Another point, in my opinion an auto box is better off road. You have no loss of momentum when shifting gears which makes a huge difference when trying to maintain speed or accelerate up a hill. This is even more noticeable when towing off road.