It's an extremely addictive series for primary school kids, and I owe to it that fact that my kid really got into reading. Finding that book which your four year old would want to listen to for 2 hours straight is a tough job. This was the one for us, followed by the whole series up to 130-storey.
But... well... it's ridiculous. There is no real story, there are no teaching moments, there are silly jokes, it's just annoying to be perfectly honest. First read-through was mildly entertaining, but by the time we started our 10th I was contemplating tearing my eyes out... And it's by far not the only book we read 10 times, no... most others I tolerate and some I even enjoy.
In any case, there is no harm in it to get your little one interested in getting lost in a book. But be sure to mildly navigate into a more sane territory after the novelty of it wears off a bit.