As an anti-astronaut weapon, I have found damage pulse somewhat unreliable; as far as I can observe, the damage is only applied when the bubble animation reaches its full radius (my testing may have been flawed or bugged, and I have not yet re-tested). Personally, I favour cannon/cannon/overdrive currently: a block count of 1:1:1 deals 9 damage a shot (90 DPS), easily flattening astronauts in the confined quarters of a ship. Some space is required to install such a turret, but the effectiveness and reliability is significant (and if you are pedantic enough, you can create open space all around it, and place the turret axis inside the base's hull, rendering it practically impervious to cunning boarding maneuvers).
As a primary weapon, it is incredibly limited in usage, especially since the game doesn't make it easy to pilot a ship properly at "melee" range (no relative velocity display or other complex controls, and significant collision check lag). Using pull or stop effects to hold a ship in range, while probably viable, requires significant block counts that could otherwise be spent on any of the actually reliable weapons.
I think it would be quite interesting to consider what could make it viable, personally. Does the radius need buffing? Should the epicentre of the bubble be offset further forward from the output? What if it launches a "projectile" directly forwards, which then explodes after X distance or on impact, whichever condition occurs first?