Certain things, the film portrays better. Other things, the book kicks butt.
Scenery wise, holy smokes Batman! Mr. Jackson did a great job presenting Middle-earth to us on the big screen. New Zealand was the perfect backdrop and I can't wait to go to the country, one day, myself just to see the beauty of it.
As far as battles, Mr. Jackson also tops the Professor with this one. I believe the Battle for Helm's Deep, in the book, was described within a matter of a page. Maybe.
One thing the Professor does have going for him is that it's everything. No skipping anything (including second breakfasts!). You have Tom Bombadil, you have Imrahil, you have Beregond. Characters that I thought were great, but because of a lack of time, were ignored for the movies.
Therefore, I must plead the 5th on this one. Both are great.
"Outside of a dog, a book is a man's best friend. Inside of a dog, it is too dark to read." -Groucho Marx
"Therefore I say: EÃ¤! Let these things Be!" -Eru Iluvatar, The Ainulindale
, The Silmarillion