Manual Hubs are always locked when engaged and both wheels will always turn, auto hubs are more convenient but have to usually move an entire rotation to engage, so if you get stuck before engaging you still won't have 4wd. Also auto hubs are more likely to fail than manual hubs, a vacuum line can crack, etc. If you are only using your 4wd the way you described John then the auto hubs will be fine, If you are doing some more serious backs woods kind of stuff you will want not only manual hubs but also a manual transmission and transfer case.