What's the difference between a dually truck and a single wheel truck?

Other than the fact that a dually truck has more tires. I'm thinking of buying a Ford truck when I save up enough money. I know that I'm going to see single wheel and dually trucks. I'm not looking for something made this year, I'm looking at trucks between 1994 (because before 1994 Ford did not have airbags in trucks) and 2003 (my dad has a F350 2003 truck that he loves). I included that because I'm sure that people are going to leave an answer that says "ford sucks", that is your opinion. I don't really like the newer Ford trucks. I got a friend who loves Chevy and hates Ford but we can still talk about trucks without a problem. I'm not a huge fan of Chevy but I don't hate their vehicles. Back to the point of this question. Does a dually truck have more torque, power, better off-road? If dually's are better off-road then I would like to know this because I go offroad a lot.

Both Ford and Chevrolet make GOOD pickup trucks. The only difference or advantage of a Dually is that it can carry a heavier load in the bed. The engine and drivetrain are the same.