Here's the most helpful advice I can give (roll eyes).
Buy a used version of whichever of the three interests you most. Listen with it in the system and out of the system. Concentrate on not allowing your desire for the conditioner to work influence what you actually hear. Write down on a pad of paper the differences you discern, if any.
If after a week or so you decide the conditioner is worthwhile, then keep it.
If not, sell it for what you paid.
Buy a used version of whichever of the three interests you most. Listen with it in the system and out of the system. Concentrate on not allowing your desire for the conditioner to work influence what you actually hear. Write down on a pad of paper the differences you discern, if any.
If after a week or so you decide the conditioner is worthwhile, then keep it.
If not, sell it for what you paid.