I found this really enjoyable; not something I would have picked up myself. I've never read any TP but I do actually like the comic/sci-fi/fantasy genre; the tone reminded me of the Hitchhiker's Guide to the Galaxy books which I loved as a teenager.
It came across initially as being quite critical of religion, similarly to the Philip Pullman books, but then as it goes on, supernatural and inexplicable things do occur. I really liked that TP seems to venerate the questioning and experimental mind but leaves room for the possibility of magic.
There's a bit at the end which seems to imply that his target audience for this is children; this didn't occur to me until I read that but I immediately thought I would love my dcs to read this when they're older.