I had "meh" results with cannons, probably because i'm used to plasma. Gimballed cannons can do an ok job at killing a large ship but... i don't know, they're missing something. The slow projectile and low damage radius make them midly effective at killing ships modules because it's very easy to be a bit off and just damage the hull (or to miss completly).
Beam lasers aren't bad at all vs modules if you're accurate enough, they're doing a fine job vs large ships you can tank (usually the low bounty one) and allow to stay in location for a longer time.
Plasma are great vs large ships modules but hitting a small ship is very difficult and you may need another weapon in order to do that. Since they got a large damage radius the projectile speed is ok, you can miss a bit and still deal a lot of module damage.
Railguns are very good, but i find them really hard to fit for pve or to fit at all because you have to sacrifice a lot of stuff on many ships. (plus, low ammo make you travel back to a station all the time)