I'm looking forward to train for some kind of dictor. I can't really see the use of getting in the smaller of the two kinds.
Is it easier to catch small ships or what?
The Heavy Interdictor (HIC) is way more powerful and useful than the Interdictor (DIC). The only use for a DIC that I can think of is for burning to the gate really fast to be able to jump through and throw up a bubble before the victim can escape - the HIC is not really fast enough for this. (The DIC also has treble the warp speed of the HIC so could catch targets that managed to warp away from the first gate camp.)