I like them both, but get more duds with the phantom soft-tails…. But when I get a good phantom softie it produces well.

Not sure if my thinking or logic are correct, but it works in my feeble mind…
I like hellhounds because you can get a really wide glide, the tail on them slows that down, and reduces that advantage. If that is what the particular situation calls for they are my go to.
I like phantom softails because they run really well (and consistently), but is a much narrower glide and a very effect wobble and fall when paused. Again, when the situation calls for that type of action, that's my go to. Now figuring out which action is best at the right time is the trick.

Saw a FB post recently about current Phantoms being thinner than the old ones and with different action so maybe you are looking at 3 different options. Four if you throw in the Chaos round nose.
An old 6" Phantom Softtail in sucker pattern is one of my best producing baits.