Each tranny option has its pros and cons... Growing up and owning 20 manual vehicles (yeah 20...) I feel in love with manuals. My first auto was a '80 Celica, and I hated not being able to shift... but it all changes when you are offroad. I have found that the Auto is a better option for offroad, due to the fact that you can have one foot on the gas and one on the brake elimantind double clutching. On my rock crwler Jeep I had a hand throttle monted on the shifter to prevent clutch slipage and be able to have one foot on the brake and on on the clutch. Also in the Tacoma the Auto is more reliable and has a longer life than the manual (however it is a great manual and last longer than most other manuals I have ever owned.)
Being off chamber and on a slope and worring about the clutch and stalling is a manuals down fall when load with weight. However in decending situation I would prefer the manual to help save the brakes by downshifting along with braking. That is sole thing I miss the most since I got my DC, not being able to slow down by down shifting. With a manual on a rocky hill climb and while learning the clutch it is easy to spin the tires a bit during the learning curve, therefore, I see this as a downfall to the manual... Toyota did come up with the cleaver clutch overiride button to help the startup in a stall situation on a slope.
So overall it boils down to personal preference. And if I had to choose between one or another in my DC, I would have to sit down and think about it for quiet a while... and think I would end up with a Auto, just for the fact that it makes it a bit easier when the pavement ends, and might last 75,000 mile longer than a manual.
Hope that helps a bit... so hard to decide though!
Wil