User blog comment:Xilinoc/Ch. 550 - Blazing Bullets/@comment-5657895-20130928233056/@comment-8669536-20131001172623

I don't really like Suì-Fēng or Hitsugaya either, but they most certainly are strong and interesting. And they're both stronger than Mayuri. If you need any confirmation of this look at the Battle data that Kubo has provided, they're in the Powers and Abilities sections of the Captains.

Mayuri is one of the weaker captains, he lost against Uryū in the Soul Society arc (although Uryū did use a super overpowered technique, so that battle isn't really a good example) and he would have been easily killed by Szayelaporro hadn't it been for him having infected Uryu with surveillance bacteria so that he could see the early parts of the fight and replace his organs.

And if Szayelaporro hadn't accidentally infected himself with the Superhuman drug through Nemu's body, the fight would have been much longer and there's no telling who'd have won. I'd say that Mayuri and Szayelaporro were the same level, and Szayelaporro was only the eight strongest Espada.