Whatever you do, don't buy a new Ram without the Aisin transmission!! Especially for hauling a camper... or anything!
Things like that matter, a lot. Sure, it'll drive around the block and down the road on a test drive just fine with any of the transmission options but the Aisin will last longer under a big load, transfer more power to the ground rather than waste so much of it slipping, and generally it's a superior piece of hardware.
I doubt I'm allowed to plug another forum here but there are good forums dedicated to those trucks where you can learn a whole lot more about them than on here.