Ok, so I came into this as someone who already enjoyed the movie and I have to say, the book is much better.
I adore Howl's Moving Castle! It's so whimsical and different. There's a lot more characters and if I'm honest, I liked the story more in the book. It's so much more detailed and there's a lot more loveable characters.
Sofie is one of my new favourite protagonists of all time. I love that she's so shy and afraid but once she's turned elderly by the witch, she's like "well, can't get any worse. STFU Howl, I live in your kitchen now" and just becomes a boss-ass bitch. I laughed out loud several times. Calcifer is great too, exactly how I'd imagine a small fire demon. Howl is hilarious in the book. He's so dramatic about the littlest things.

Howl's Moving Castle is just a really fun time and put me in a great mood three days running.