As you can see, CW, there are as many opinions as weapons.
I do tend to favor the Phased Polaron Beam since it's so cool to just skip shields and start damaging the enemy immediately. In the default game this advantage goes away when phased shields are available, though. I've modded my files to include a new weapon after the PPB that skips ALL shields. It's larger and more expensive both to construct and to use (more supply usage) but it lets me keep the same basic strategy and I think makes the Sergetti as dangerous in the late game as the early/mid-game where they've just got their PPBs and phased shields haven't appeared yet.
The Ripper Beam is a very nice weapon but hard to get quickly. You need level 7 propulsion before you can even begin to research it. If you're playing max-tech, then what the heck. Put a tractor beam or two on your ship (extra in case of a miss) then a bunch of Rippers, then a repulsor beam. This makes a wicked, nasty brawler that sucks the enemy it, pounds it with very high damage and then repulses it out of range if there's anything left. If the target is of similar or smaller size there usually is
not anything left to be repulsed away. The Ripper has a very high damage/size ratio. But then if it's larger you cannot pull it in with the tractor beam.
The Null-space Cannon is certainly not something you want to rely on completely because of the slow reload, but it can be a good "auxillary" weapon that lets your ships start damaging the enemy immediately. Just one NSC in a ship with otherwise normal weapons, for example. Using a Tractor/NSC/Repulsor combo might be even nastier than the Ripper setup. You can use the repulsor to keep the enemy away while you are waiting for that reload, too.
And the NSC makes a great ambush weapon to put on Sats guarding a warp point.
[This message has been edited by Baron Munchausen (edited 11 August 2001).]