I think that guns are currently the strongest weapon type.
Why bombs are bad
Bombs fail because of how they can't handle single target foes very well, with the exception of dark retribution, which is but one bomb limited to shadow damage. If I want to bomb vanaduke, my damage is going down the drain because vanaduke isn't 20 mobs, he's one mob with one health bar that takes forever to reduce. The same goes for tortodrones and every other large mob.