This is the good old imperative-vs-declarative debate. jQuery is "(I think) I know what the current state of the UI is, make these changes", React is "I need the UI to be in this state, you figure out how to get it there".
In my experience, with jQuery you spend a lot more time making sure each and every event handler puts all UI elements in a correct state, often repeating yourself or calling the same helper functions. With React, all that computation is concentrated in render(), making it easier to reason about. And if you need to add a new UI element, reviewing all jQuery event handlers will again be a lot more work.
Of course, this assumes you are working on a real SPA with a lot of dynamic state, not on a reddit clone where all you need is a reply button to hide/show a textarea and a hidden field to track the parent post id.
In my experience, with jQuery you spend a lot more time making sure each and every event handler puts all UI elements in a correct state, often repeating yourself or calling the same helper functions. With React, all that computation is concentrated in render(), making it easier to reason about. And if you need to add a new UI element, reviewing all jQuery event handlers will again be a lot more work.
Of course, this assumes you are working on a real SPA with a lot of dynamic state, not on a reddit clone where all you need is a reply button to hide/show a textarea and a hidden field to track the parent post id.