>>2093782
Hephaestus is pretty good. It's better than Devastator and Hellbore overall according to one nerd who gathers statistics on the forums, as well as my own anecdotal experience.
It's a good general-purpose large slot weapon. It has good ROF and projectile velocity, making it useful against most targets.
Very safe choice for large slot, Mjolnir cannon is probably better generalist if you can handle the flux, but most ships can't.