depends a lot on what you need, what the 6kW can offer, what it costs.
Do you need more precision or finer detail than the Oxyfuel or plasma can give you? Do you need the reduced HAZ depth that laser <should> give you?
Does the laser you have access to cut well? is the motion system smooth and accurate enough to give you the edge quality that you need?
start with the laser mfg's propaganda/specs
go from there...
let us know!
Jay