If I were a man with a beard, or a wife with a husband with a beard, by the time I got to page 5 of The Twits, that beard would have to go. Dahl's description of beards in general, and of the various refuse that made its home in Mr Twit's beard in particular, had me wincing, and Blake's illustrations made it that much worse. Yuck! Mrs. Twit doesn't fare much better. She's mean and hateful and cruel, a most terrible, horrible woman.
The Twits is more gross than dark, and pretty humorous. If I were going to read Dahl to a kid who might not go in for the darker, scarier stuff, this is the story I'd choose.