There are a number of cut down methods availble : Hot Wire/Resistor, Pyro and Magnetic.

Pros :

• Low power use.
• Light.
• Very fast.

Cons :

• Explosive - duh.

Pros :

• Safe.

Cons :

• Can be slow.
• Can use alot of power.
• Can be mechanically fragile.

Pros :

• Safe.
• Fast

Cons :

• Can use alot of power ?
• Heavier than pyro/hot wire ?

Magnetic cutdown