In looking at martial arts training with weapons, keep in mind that most of it is theory and a lot of it is for show. When you see forms (Katas) with weapons a lot of time you see a lot of twirling and spinning. You see light weight staffs and nunchaku so the can move faster. Real weapons have a little more weight to them and you won't be spinning nunchaku in a real fight because you don't want to drop them. When you hit with them you have to hit at an angle toward the end so that they don't bounce back at you. Most of your swings will be at a 45 degree angle. You won't be releasing them and flipping them. All that is for show. You see demonstrations with the nunchaku against other weapons (usually a staff or a sword). The look good, but the nunchaku isn't that effective against the longer range weapons. They work best as an element of surprise against an unarmed opponent. The Octagon shaped nunchaku provides a good edged angle to cause a nice blunt force trauma attack. They can severely bruise an opponent and can be used to break bone. They can be used to choke or be twisted around a joint.
The staff (Bo) is a long range weapon for blunt force trauma. You will see 2 martial artist dual with the Bo but real combat won't look like the demos. If your opponent gets in close range, it's going to be hand to hand.
The tonfa is a good one. Because it is like re-enforcing your you forearms and extending your fists. You can fight better with this one over the others in my opinion. The cops use this one.