I just read a review of the Chronicles of Narnia in Time, and I can't figure out what the guy's talking about. Maybe it all comes down to having movie reviewers who are illiterate. If they can't read, then they certainly haven't read the books on which the movies they review are based. This would at least give a reason for their thinking that Narnia is a rip-off of Harry Potter.
I mean, good grief, these books were written in the 1950s - unless C.S. Lewis had some amazing psychic powers, I'm pretty sure he never read any of the Potter books which weren't written until decades after his death.
As to the similarities (?) to Tolkein, they were friends who read their books to one another as they were writing them. These guys knew each other's work, and also knew the original backgrounds of the mythic elements they were using.
OK, now you're (perhaps) wondering what I thought of the movie. I found it spectacular. Unlike the Time critic, I found the child actors to be quite excellent. Perhaps he's never experienced emotions beyond fear of explosions and the joy of destruction in a film, but Lucy actually portrayed a very wide range of emotions very well. The special effects were quite special, and the changes made to the story line from the book were quite acceptable to me. By that I mean that I understood that they had only a 2hr period to give us all the background that the expository text of the book would normally convey, so they added a scene or line here and there to give us a quicker glimpse into the relationships among the siblings.
About the only thing I missed (and they almost gave it to me) was the part where the children ask the beavers if it's safe to be around Aslan. The response is that of course he isn't safe - he's not a tame lion, after all - but he's good. They came to it at the very end when Lucy and Tumnus are watching Aslan leave, and I felt it worked well there, but it was still missed at its original spot.
All in all, I loved the movie, and would happily go see it again. I certainly hope they've had enough box office success to assure us at least the next installment in the Chronicles!