Which transmission is better for off-roading is a debate as old as the automatic transmission itself. Pros and Cons are:
Automatic
+ Low speed throttle modulation
+ Ease of use
- Maintenance complexity
- Length
Manual
+ Ability to engine brake on steep downhills
+ Ease of repair
+ Increased driver participation (fun)
+ Affordability
- Increased driver participation (not fun in traffic)
It really boils down to buy what you enjoy. Then, think up arcane reasons why it is better so you can argue with your buddies around the campfire.