not sure why Nike's light version is being shit on so much, but she's VERY useful in DMM's accessory quest rank 5, as she makes two full bursts in a row possible... rank 5's nuke literally wipes out an entire team in one go, so making her stunned guarantees the win. Nike is closest to guaranteeing that than any other. you just need to know how to use her, not that hard...
both are good kami to have in different types of battles... Nike for access quests, thunder Aphrodite for long battles such as raid ragnaroks or guild order... you can't compare the two, they're completely different... one is a healer, the other isn't..
enough arguing over it.. it's pointless, lol