Stephen Ede |
It's an interesting question. Because Rings of Wizardry I and II are massively overpriced compared to Pearls of Power.
It's not until Ring of Wizardry III they are decent and 4+ they are superior. And even then the maths depends on what level you are (i.e. if you are only high enough to get 1 or 2 spell slots from your class they aren't worth it)