I've been using her for months now .. and she's really great.
Fire/Water barrier, immobilizes, accupunctures, ignites, deals "high damage", buffs males, low cd,

You c*e her with ao which is an ordinary Kage ninja and you'll be able to use her 60 chakra mystery round 2 for sure (unless you meet chakra *ers)

And people are still using her in late stages of the game.

And if you get lucky and get Chojuro too .. you'll use the mist team (Ao, Chojuro and mei + Gamaken) which i use and find very balanced.

So bro, if Hidan is around 12K / 15K in events (and he's not worth it imo) Mei is worth 13K for sure !