I think they can have there uses exept a few like crytoscrambler, mining lance, the heat laser and to an extent the disruptor laser and grom missiles as you can have then have them on regular you just get the added bonus of a second effect.
Prismatics are handy if you got the power.
Hammers arnt much more effective than regular but are easier to get hits with.
Apa are good for sustained fire, so target lock can be aplied more often.
Enforcer cannons do realy good damage if your in a small ship.
Packhounds are just plain awsome for removing the teeth from your enemy and are much harder to counter than any other missile.
Pacifier frags are like extenede barrel shot guns and are much better at all things frag unless your huging one another.
I dont think i have missed any.. but i will say that it kinda depends on what your edge is as to whats the moste usefull.