Ignore pointless comparisons about how it pales in comparison to Lord of the Rings. This isn't Lord of the Rings, nor is it Citizen Kane. Why some fools insist that every movie must be measured by the yardstick of their own personal favorite I will never understand.
If you're so spoiled by state-of-the-art computer graphics where each creature has an entire team of people working on it, and can't appreciate the human creativity and craftsmanship of great stop-motion animation, don't waste your time on this movie, go watch the latest Pixar release.
Harryhausen's work is remarkable not because it's the most realistic animation ever, but because he was able to achieve remarkable things with sculpture and movement on a budget comparable to today's 30 second ad spots.
Tom Baker steals the movie. He's terrific as the evil sorcerer, villainous but with enough humanity to his character to make him at least somewhat sympathetic.