Dodge always tended to have substandard transmissions, no matter whether they are auto or manual.
The NV5600 is a heavy, crappy shifting turd, the NV4500 has a big 5th gear problem, that's somewhat been addressed.
It also has a wide gear spacing, with large gear splits, which are a carryover from the 4 speed manual days.
Their 4 speed automatics (47RH, 47RE, 48RE) tend to be problems, but fortunately a few aftermarket companies have a handle on those issues.
The 68RFE is a qualified disaster, having too many under-sized parts for 325+ hp.
The GM ZF-6 seems to have a very good reputation for durability, from what comments I have seen about them.
As does the Ford version.
I truly think Dodge doesn't do much R&D that involves real world situations, such as pulling 35k plus for 10s of thousands of miles, or driving through high altitudes pulling heavy trailers.
Never mind the lack of R&D and such on their front end steering components, which is apparent by all of the recalls on said components in the last decade+.
Mark.