What raises To Say Nothing of the Dog far above is that there is more to it than just trying to elicit laughter. There are the intriguing logic and logistics of time travelling which Willis beautifully worked out. The characters are also generally amiable and as something of an anglophile myself I enjoy the British culture references like jumble sales, the “tube trains” and the Jeevesian acerbic butler dialogue.
To Say Nothing of the Dog is not a laugh-a-minute book, it is not a complete success as a comic novel, but neither is it a failure. More importantly, as a lighthearted time travelling sci-fi novel it is worth a read. Just don’t go into it with the wrong expectations.
I think would be fine to read if you'd never read any of Jerome K. Jerome's writing, but I think a familiarity with his work makes this book even more fun to read. The little summaries of action at the start of each chapter, the many references to Jerome's book (and even his person!) during the first part of the book, and even to some degree the measured, deliberate pacing of the book all stand as tribute to Three Men in a Boat: To Say Nothing of the Dog.