I've encountered a number of guys who were extremely pleased with Amsoil Universal in their Chrysler transmissions (46RH/42RE/45RFE). Improvements were perfect shifting from start in the winter, less slipping, cooler temps towing, etc. Two are friends who regularly haul substantial (>5K) loads. They'd shoot me before going back to dealer +4 fluid, let alone department store +3.
To my knowledge, the only "modern" Chrysler transmission that's okay with Dexron is the AW4 (XJ's & early '93 ZJ's). Those can use ATF+3/+4 or Dexron, but it's an entirely different beast.
Redline makes their C+ ATF which was supposed to be +4 compatible. Noticed their website only says 7176 compatible now. (Someone kick their webmaster for me. 45 seconds to get to useful information.)
I'll go along with a previous post that said you must be prepared to switch back if the fluid isn't performing for your vehicle. For whatever reasons, some transmissions seem more particular than others, even of the same model.
David