It's hard to compare a 5 speed auto to any of the previous 4 speed autos, because the biggest disadvantage of the previous autos were lack of gearing options and too high of gearing. I think the new 5 speed auto addresses those concerns quite nicely.
Autos have a real advantage off road, except for engine braking downhill, but a lot depends on how much control you have over the gear selection if you want to go to manual shifting.
I don't have any idea how the new Taco trannys behave, but I know for example, my wife's Forester tranny could care less what gear I put it in or what gear I want it to be in. It has a complete mind of it's own and usually doesn't shift when I want it too, especially not downshifting to pass, which is frustrating as heck. That's just the way the Subaru designed that particular tranny. It was all about fuel economy and nothing about performance.
So, I'd do some research and test driving on the new Tacos to see how much manual control you can have and if they downshift when you want them too, will hold a gear to redline, and will stay in gear on an obsticle when you want it too.
For my purposes I'd rather have an auto to free my hands to work the GPS, computer, radios, etc.