I agree with Tolkein about Lewis. Also, Lewis is far more popular in the US than he is England, where's seen as rather immature. Food for thought.
Well, I am in the process of finishing a review of a book about Lewis for Mallorn, the journal of the Tolkien Society. Last year, I* wrote an essay for Mallorn about the influence on Lewis of David Lindsay's A Voyage to Arcturus. Given that Mallorn comes out of England, there must be some people there who still take him seriously. I think his fictional masterpiece is Till We Have Faces, which is a very good book. I also think that Out of the Silent Planet is very good. As for his scholarly work, The Allegory of Love in particular is an essential work. Taken on his own terms, Lewis is excellent -- and I am too loyal not to defend a writer who has been entertaining me since grade school; he is a writer you can come to love, like Robert Louis Stevenson. Unfortunately, his admirers often place a weight upon his works that they were never meant to bear.