I'm afraid I'm not near my charts ATM but this will have to do. They more or less show what's up.
The problem with "all Ballistics" is that includes everything; there are better / worse in every category.
If we are talking about Kinetics, the Light Needler is the best choice. It's way above par on efficiency, range and DPS. But, unless you know who to farm them from and have some patience, their rarity can be annoying. Next after that is the Railgun. They're both supremely more efficient at flux-locking opponents so that other weapons can efficiently take down Armor. The only Vanilla weapons that are better are the LMGs, but they lack enough range and in a heavy fight in late game, they rarely are worth spending Flux on.
The Arbalest is trash and the Light ACs aren't much better; the Heavy AC's all right if nothing better's available, but not great (Railgun is superior). It's arguable that the HVD is good simply because of range, but if the enemy can close the distance or you want to finish things before CR begins to bite, you want Railguns and Light Needlers. HVD only looks good to armchair commanders, IMO; it keeps your ships at arms-length, but it can't finish things. Better to invest OPs in the ability to close the distance.
Unfortunately, that's it. Gauss is worthless; too inefficient for what little it does, Storm Needler simply doesn't have the efficiency to be more than a burst-alpha, player-only gun with only a marginal use case (I made an Onslaught once that did all right with one).
In HE, the Heavy Mauler is far better than anything else. Good firepower, supreme range, reasonable efficiency. The only other HE worth mentioning is the LAG, which is all right but nothing special, and the Hellbore, which is largely inferior to the Heavy Mauler but has high-enough single-shot alpha to be considered.
In Frag, the Flak is superior to the Dual Flak, for OP efficiency. It also outrages the Dual Flak by 100 units, which really adds up if we're talking late-game ITU and character buffs and ECM. I don't think the Vulcan's worth 4 OPs; in late-game play, 4 OPs spent on Venting is better and missiles should be dodged, shield-tanked or Flak'd, in that order.
Thumper remains a gun in search of a job; if Armor-less fighters were a thing, it might have a point, since it's the third-best Flux-per-Hull gun in the game. But Hull matters so little I general that it's hardly worth considering.
Megas is entirely right; for no particular reason, one of the most efficient Energy weapons in the game is in Ballistics. Unfortunately, it's almost entirely a player-gun, because, like the Storm Needler, it tends to be a terrible choice for AI ships.