I loved this book when I was a kid, so I was happy to find it stood up to adult reading. It's refreshing to find a tale of psychic children who use their powers not to save the world but to make their beds, harass their babysitters, and generally act like kids
. The conflict arises from misunderstandings between kids and adults, not some evil opposing force.
In short, there's no "with great power comes great responsibility" here, just good old-fashioned fun. And it is old-fashioned in a certain sense--the book is very definitively set in the late 1970s, with fashion and child-rearing attitudes reflecting the time period. But I think it would still be enjoyable for a modern elementary or middle school student.
My memory had the book running much longer, so I was surprised to see it ended where it did. Pity the author never wrote a sequel.