Finally caught this at last today and you guys are right, this is a totally unexpected delightful little gem. The way Vaughn balances the disperate tonal shifts and makes it all work, the way everyones obviously having such a great time, the way the film is a fantasy fairy tale that doesn't need to feel satirical or post modern, yet still manages to be funny and touching in all the right moments - I just had an absolute blast from start to finish.
My missus rightly commented about halfway through "now we know how good The Golden Compass could have been with a great director" and she's right, Vaughn would have fucking nailed His Dark Materials.