Without engineering...
- Beam lasers give the best burst DPS, but run out of puff very quickly. They're good for taking down small ships quickly, or on ships with lots of distributor capacity.
- Pulse lasers have the lowest distributor draw giving you better sustained DPS.
- Burst lasers are the weird middle child. They supposedly have the best damage per energy, but I can't think of any builds where that'd be more useful than beams or pulses.
The best bet is to keep trying different combinations until you find something you like. You don't lose any money selling used components, so swap them around to your heart's content!
With engineering, I usually only use beams. They can be made to fire indefinitely, and have better DPS than overcharged or rapid-fire pulse or burst lasers. However, on a ship that has a weak distributor or powerplant or is overloaded with lasers, burst or pulse may be a better option.
As for the KWS, I prefer it on a second trigger in case the target dies before I've fully scanned it, or I have to stop firing for whatever reason.