As far as I know, the adventure with the cyclopes, Polyphemus, is in Book 9. The encounter with Circe is in Book 10.
If you are just comparing Odysseus's adventures with Polyphemus and Circe, I would have to say that the encounter with the cyclopes is a great deal more exciting than the one with Circe.
In Book 9, the encounter is much more chilling. The men are really in mortal danger and it is not clear how they can escape the monster. In Book 10, Odysseus actually has it pretty good, being the lover of Circe. His men are turned into pigs, but they are not being eaten and they are soon turned back. So that really seems like a vacation compared to the encounter with Polyphemus.