I think Tolkien was a really shitty writer and I could never get through anything he wrote despite trying multiple times. I do think the movies were great and the story from start to finish in those had me captivated. Rowling ain't a great writer either, but I've read through the Harry Potter series like 3 times. The movies for those weren't great IMO. I gave up after Goblet of Fire. I ended voting for Harry Potter for two reasons:

1. I put a lot of weight in how much I enjoyed the original source material.
2. Emma Watson