It's pretty obvious Sasuke is more powerful than Mei --- Kishi made him that way. Heck, he made all the Uchiha that way.
But the fact is this: Mei, without the help of any OP Dojutsu, or pesky side-kick (read: Zetsu) was able to give Sasuke a good thrashing. Yes, I think melting through his Susano'o, and then burning his skin, and
leaving him defenseless with no hope of retaliation, counts as having the upper-hand. Think about it:
Sasuke was basically on the defensive THE WHOLE DAMN TIME. He had nothing on Mei. NOTHING.
He couldn't even land a hit on her while being smothered by her acid mist.
And i daresay even, Mei was toying with him.
She didn't have to wait for her acid mist to melt him; she could've easily followed up with a torrent of lava that was bound to incapacitate him. But plot-no-jutsu made sure Mei was portrayed as a Uchiha-loving sl**, who decided to
play with her food a little while longer before eating him.
So yes, Sasuke is objectively more powerful than Mei, thanks to his OP dojutsu, but Mei's performance at the Kage summit proves that
she's no push-over either.
PS: Why do people think that Raikage is more powerful than Mei? Yes granted his speed is his primary advantage, but his attacks are NO WHERE nearly as destructive as Mei's. Think about it: it cost Raikage and arm to even hurt Sasuke. Mei just had to open her mouth
