Composers? For Czerny, yes. He wrote amazing sonata's and stuff, at the level of Haydn and Beethoven, just no one knows about them.
Hanon is good if you start playing the piano, when you're more advanced, Czerny is the way to go. Czerny also teaches you to play techniques with an accompaniment, Hanon just makes your fingers more flexible and gives you more control over your fingers, and that's it, but Czerny does all that as wlel.