"The book is always better." It's a saying for a reason. That doesn't mean it's always true.
From the first few scenes of Tim Burton’s Miss Peregrine’s Home for Peculiar Children, it’s pretty clear that the film won’t be a 100% faithful adaptation of the book. Therefore, if you’re someone who read and enjoyed the book, which I am, you must decide quickly – do you constantly compare the film to the source material or do you try to enjoy it as a separate piece of work. I’d suggest the latter.