Yeah, I wouldn't say this unless I knew I was among other parents of kids who are really strong readers. However, I think I might say something like "The His Dark Materials series is a good one for kids who are done with HP" or "I've heard good things about the His Dark Materials series."
See, though, I chose the example with care so that it couldn't be wriggled out of so easily :-). Your version is strictly less helpful to the person you're actually talking to than mine - this parent has already tried multiple books without success, so an "I've heard" or an unsupported assertion is not nearly as useful as an actual positive experience by an actual child - she probably chose the previous books on the basis of similar assertions and "people say" stuff, after all! Besides, both the versions you suggest have their own problems, which to my mind are worse than the disease they're trying to cure. The first is just arrogant: who are you to make blanket statements about which books are good for "kids who are done with HP" in general? I mean, maybe if you were a librarian it would be OK to say that, but I would certainly recoil from someone who said this kind of thing otherwise. The second feels to me like lying by misleading, if the only person you've heard it from is your child who's read the books!
