Great Midfield trio, play off each other very well, close to the level of Xavi, Iniesta & Bosquet, but i would say the Barca trio are better, especially Iniesta who was unbelievable.
What i like about the Madrid & Barca midfield trio beside their obvious quality is the length they played together (at least 5 full seasons together), which provides some sort of solid stability to the team (they also had stable back 4 & GK).
Good shout is City's trio of Fernandinho, KdB & D.Silva, of course not as good as the Barca or Madrid trio, but also instrumental to city's PL successes in 2018 & 2019