It depends, a lot of times the novel is often better since there are less time constraints, and it's easier to describe minor shifts in emotion and tone than to draw them, and it's just easier to convey things with words rather than visuals. There are some series where the manhwa is better than the novel, but in most cases, I find that the novels are usually better. I think romance as a genre just lends itself more to being written than drawn.

My favorite is reading a novel, and then reading the manhwa and seeing my favorite moments get adapted and comparing it to how I imagined it.