Originally Posted by smr

unique equipment from quests are weak compared to a Warrior Ring or some of the event equipment (Halloween, Christmas and New Year).

Depends how you look at it: the unique earrings aren't as good as a Warrior Ring, but way better than the regular earrings from the mid-grade equipment seeds. So once you unlock that second jewelry slot for a girl with personal earrings, they're the best thing you could put there.
For event equipment, the event earrings are pure defense, which is a rather useless stat in our game, except for Counter Girls. So personal earrings > event earrings.

I like keeping my event sets together though, and because of their high defense, also prefer to put them on counter-girls. So Hypericum and Mirabilis both wear a full set, making them totally overpowered. I'm also trying to get rainbow dress blooms for Anemone, so she can have a personal event-set as well. I haven't spotted gold dress blooms in our game yet, but once I get my hands on those, they're going to Rose.