Just finished it. It was ok. The anime was better. That usually doesn't happen, the movie being better. I liked the characters and they were portrayed well but a lot of it didn't make much sense and it felt rushed at the end. Specifics:

(SPOILER)
Sophie falling for Howl in the end was kind of awkward. I knew it was getting to that point but I didn't think it was all the way there when the end came.

The whole Miss Angorian/fire demon stuff was confusing and didn't make sense at times.

I still don't know what the connection between Wales and Ingary is, and how/why Howl is involved in both worlds, but I guess that is solved in a sequel.

It was a good read but nothing amazing.