[Bear_Slayer]

For those who have, how does C.S. Lewis compare to J.R.R. Tolkien?

I can't speak with regards to book comparisons, but I do know that Tolkien and Lewis were acquainted and influenced each other.

[AnAmericanMother]

I can highly recommend the Narnia books -- although they're clearly written for children, Lewis has a good time winking at the adults who are reading the story to the kids -- lots of humorous asides that will fly right over the kids' heads . . . e.g. "In Calormen, children are taught storytelling as English children are taught essay-writing. But everyone wants to hear the stories, whereas I never heard of anyone who wanted to read the essays . . . "

You will enjoy the books very much. They are not as "epic" as LOTR -- more like The Hobbit or Tolkien's little jewels Farmer Giles of Ham or Smith of Wooton Major. But the worldview is similar, expressed differently but similar. As others have observed, Lewis and Tolkien were good friends and read and discussed each others' work.