Have you seen the ReactConf talk on hooks? [1] It's absolutely worth the watch, even if you're somewhat familiar with hooks. They go through the pitfalls of class-based components and how hooks solve them.
It more-or-less boils down to: 1. class-based components force your lifecycle logic to live in disparate locations. 2. Class-based hooks are obtuse with hidden gotchas whereas pure functions tell you exactly what they're doing. 3. A whole class of unergenomic solutions disappears when you use hooks.