Really does depend on the build and/or ship focus. Engineering also has a lot of relevance here- engineered weapons can really change the nature of how they're used.
Unengineered, keep in mind the following:
Pulse is most
efficient on energy- but does the least damage
Burst is a
mixture between efficiency/damage
Beam is high
damage but really
sucks for efficiency unless you mod it
Pulse you can spam almost constantly, given enough power pips into weps and also most heat efficient can really bring down shields quick, Burst is kinda iffy on spamming- mainly because of the cooldown times between shots- and it's more difficult to line up shots, Beams you can spam as long as you've energy but will really kick your heat up the longer you hold it. Beams are pretty much "easy mode" lazorz.
The most obvious intent of "lazorz" is pretty much for
melting shields- for hull/armor damage you'll want to combine with kinetics/hybrids anyway. The exception to this rule of course is the higher grade the weapon, the more sustained damage it's going to do (Vulture with x2 Class 3 Pulses, for example) especially against ships smaller than its own size.
It's also a hotly debated topic as to mix weapon types- or go with singular focus- especially when Engineering comes into play... there's just so many different combinations you can mix/match that it really comes down to your own personal preference unless it's purely situational (high shields/low armor, or vice versa) and I've seen a lot of people go with pure hybrid damage types (plasma accelerators, etc.) with fixed instead of gimbals/turrets to maximize damage, too. These days very few "speed/hull/armor tank" and shield "stacking" seems to be the current "meta".
My personal favorite is the time-tested gimballed/fixed pulses with fixed kinetics of some sort (missiles or multicannons) so basically once their shields are down, I can either snipe at their specific modules, or my other weapons are eating away at their structure until they stop moving. I've been known to switch it up, though.