Howl's Moving Castle, the book by Diana Wynne Jones:
This book is uniquely written. It has fantasy and magic and a unique main character who believes any adventure she engages on is doomed to failure because she is the eldest daughter and everyone knows the eldest always fails at adventure...
The book contains more magic, in a way, more worlds and covers more real estate, let's say. But I found the plot at times confusing, not very coherent, and a bit meandering. I felt there wasn't really a big "point." Mostly it was Sylvi rambling. Even the romance is more a faintly implied thing than an actual occurrence. You kind of think Sylvi and magician Howl might grow to like each other despite their constant bickering, but it doesn't really develop much. Until at the end they hold hands and grin at each other and so they must be in love? ... meh.
Howl's Moving Castle, the movie by Hayao Miyazaki:
There is more plot to this story, more purpose. Howl's character has more depth, as you see that what appears superficial in him is actually hiding many things--a curse, a missing heart, and his ongoing attempts to save the world from self-destructing in war. Sylvi's character is more fun in the movie somehow... perhaps because you see her as intrinsically kind and pragmatic, rather than intrinsically dull and lacking in redeeming qualities (which is how she sees herself). The romance between Sylvi and Howl is also much more well done in the film (like it actually exists-cough). The other pieces of the plot, including the witch of the waste, the missing prince, etc. are make much more sense in the film than in the book.
So, there you have it. The book is okay. The movie is magical. If I had to choose, I would choose the film every time. But I think the book is still worth the read simply for it's uniqueness.