Racial weapons can top the standards depending on your strategy. Take Organic technology as an example. Yes, I think the standard weapons are superior in terms of range and firepower, however, replacing mineral cost with organic resources allows an empire to build ships more quickly and maintain a far greater number of ships than a standard race is capable.
That a standard ship may outfight an organic ship given all other equal circumstances may be safe to say, but when an organic fleet builds 40-60% faster, it can wear down a "superior" enemy through sheer numbers and reinforcements.
But I'm not telling you anything you don't already know.
On a different note, I do like Null Space weapons for their special ability. I would equip a large enough ship with Null Space, followed by 1 or 2 Shield Depleters, an Ionic Disperser, and then a couple of APB's/DUC's/whatever. Even though they no longer skip shields, I still have a special place in my heart for the Engine Destroyer weapons.