I'd never owned an automatic until I got the old "quarter million miler" Honda Accord... guess I got lazy after that?
Regarding the longevity of an auto... I figure the TH400's are pretty tough nuts (since they come behind BBC powered everything including 1ton CC dually's).... combined with the "weakness" of the 304 2V (guesstimating 175 NET HP) and the rest of my "throw away" (too small/too old) drivetrain... I've never worried about it... Those tiny @$$ OEM axle joints? Oh yeah! But not the automagic...
Auto by far. I see so many straights trying to do hill climbs and can't make it because of wrong gear. After several tries they finally get it, but my auto shifts for me and I keep going.
Manual with some sort of doubler and some tcase gears...all the way...
1- it'll sure make you a more competent driver
2- having the direct connection between your foot and the tires - no slush box
3- it's a much better show..."Holy hell, he grabbed 3rd and the tires are still roasting!"
For a trail rig I wouldn't have an auto...I've wheeled both...
That being said...there's a Powerglide going in my buggy...
Besides...only pansies need a gear lower than 1.76 at the trans...
That and I don't want to shift a manual backwards and I could practically fit two of them in the place of one manual...
For crawlin I like the manumatic, best of both worlds. I run a manual valve body T400, w HD planetary, but I don't find fault with those who like a MT. You just have to develop your skills for whatever you got.