The CN missile launchers are worth it over T2 if you are lobbing faction missiles about the place, they hold more and have a higher ROF if I remember correctly
If your using any kinda sig tanking setup they are useful if you can afford it as the faction ammo doesn't bloom sig like the T2 high damage ammo does.
Meta8 failguns also have a higher optimal range than the T2 and higher meta ones which can be useful but in some cases the higher damage on the others often makes them just as effective at longer ranges.