Any of the RFE trans are going to require special care both in maintenance and driving style. However I think a lot of the bad rep the RFE gets is because people tune their Cummins with 300hp tunes and blow the 68. Before 8 speeds came out, people were doing similar with Hemis/545s. Its just not a good trans platform for modified motors.
I do a drain and fill on my trans annually and a filter change every other year. So far, **KNOCKS ON WOOD**, after 9.5 years and 86k with 12k of that towing my camper all over the US, my 65 is still going strong.