Waterjet vs. Laser
Although a laser can cut light material faster than a waterjet it doesn't always mean that it is less expensive. A laser can have difficulty cutting polished material such as aluminum, stainless steel, copper, brass, etc. the reason for this is the reflective properties can mess with the laser. The laser will also have a heat effected zone, and also puts off fumes when cutting.
A waterjet has none of the above problems. Most notably no heat effected zone to cause hardening or distortion to the material. Also a waterjet can cut thicker material than a laser.
WaterJet Vs. Laser