I just got back from Dr. Ralph Wood's lecture. He's a good speaker - if any of you get a chance to hear him, do!
Dr. Wood did not say anything that I wasn’t already somewhat aware of (and I have not [yet!] read every scrap of biography about either man), but he brought out themes that were interesting. He focused on contrasting the two men in four main areas.
Dr. Wood made mention early on about Williams’ influence on Lewis as a source of trouble between Lewis and Tolkien, and Tolkien’s dislike of Joy. He later mentioned Tolkien's dislike of most of Lewis' work.
personality
Tolkien: shy, diffident, mumbled when lecturing, did not make friends easily, insular, held grudges against those who criticized his work negatively, or whom he did not agree with
Lewis: made friends easily and was deeply loyal to them (eg Arthur Greeves, Paddy Moore and Mrs. Moore), spoke well, was an “intellectual pugilist”, answered every letter by return post
craftsmanship and style
Tolkien: wrote multiple drafts of everything, laboured over every detail, thought that Lewis wrote “too many books too quickly”, thought Narnia second-rate as a mythical world, disliked direct allegory with one-to-one symbols or representations
Lewis: rarely wrote a second draft of anything (his first edit of his writing would be at the page-proof stage of publishing), characters (especially as shown by their names) and events are obviously directly allegorical
apologetics and evangelism
Tolkien: T said his writings would “neither teach nor preach”, and that they would stand on their own merits as works of art, thought the Protestant reformation and Vatican II were huge mistakes, probably resented Lewis remaining Protestant, thought Lewis should not be writing apologetics as a layman
Lewis: evangelised in everything, took a sometimes simplistic approach to theology (Wood gave his highest praise for Lewis’ “imaginative apologetics” i.e. the space trilogy and especially Till We Have Faces )
church and the modern world
Tolkien: warfare is a fundamental fact of the modern world, had a horror of war and coercive force, sought to offer an alternative to war, e.g. Frodo’s pacifism after fulfilling his quest, life and faith are community-oriented
Lewis: war had little or no impact on his imagination, e.g. attitude to war in The Screwtape Letters that war is more useful to God than to the devil, individualistic approach to faith
The two men had their strong bond in their faith, their love of the natural world, their dislike of the modern world of machinery, and their belief in the value of the myths of pagan, pre-Christian cultures.