trying to research used prostar isx15 best atm, tc10 or ultrashift?

[SemiSweet]

The Allison auto trans I find are complete dogs, never a good gear for the conditions I find either over revved or lugged to death. On the other hand, We have an Eaton 18sp auto in one of our trucks and I was very hesitant to own it at first because of all the reasons discussed. The truck is geared properly with 3.91s. Not to go against all the above but I am pleasantly surprised at how nice it is to drive. They can be programmed to to shift at higher rpm and, while pulling, its as easy as hitting a button to drop or hold a gear to keep the rpm up. It Takes some getting used but if you have bad knees then get what makes you comfortable. I would take a little more maintenance over pain. Could be hard to find an 18 speed auto in a pro star although.

Personally I like my manual and I float the gears but drive very little city so rarely use my clutch.