Tolkien was Catholic, so some of his worldview (which entered heavily into the books), I disagree with. Looking more into Narnia, there are some things I disagree with there too. I appreciate the depth of Tolkien's worldview. I appreciate how he can incapsulate in words so many concepts of the Christian faith. One of my very favourites is how God creates everything, sin enters the world, God is not responsible for sin, and yet God's plans are not frustrated by sin. This is in the music of the Maiar, close-ish to the beginning of The Silmarillion. And of course the corruption and flood. Other bits as well, but you really have to dig for them. It's not really fair to compare Lewis and Tolkien because they had different objectives and were trying to write very different books. Lewis, as a protestant, had an idea of the priesthood of all believers, whereas Tolkien thought "preaching" should be left to the priest. Therefore Lewis' works have much clearer connections to Christianity. Digging into Tolkien will find you some interesting stuff, though. Such as eucatastrophe, (Everything going from catastrophic and suddenly righting itself--as in the Battle of Pelennor Fields), Tolkien saw as a reflection of the Resurrection, which he called the ultimate form of eucatastrophe. He uses this literary form heavily.