Truggy or buggy
#2
Buggies turn quicker and are more precise. Truggies are more stable and forgiving.
#3
Suspended
Since they are based of the same vehicle type and drivetrain there are few differences between one or the other. What works with one generally works with the other. Set-up is important to either one and it's just as easy to have a poorly (or good) handling truggy as it is a buggy. I will add that truggies tend to go through fewer tires so it is easier for a new guy to be able to afford to keep tires on them.