The one unique feature in the books are the author's use of explanations for the bigger words used in the book. Here is an example:
The three Baudelaire children lived in an enormous mansion at the heart of a dirty and busy city, and occasionally their parents gave them permission to take a rickety trolley - the word "rickety," you probably know, here means "unsteady" or "likely to collapse" - alone to the seashore where they would spend the day as a sort of vacation as long as they were home for dinner.
I found these explanations tiresome and disruptive but perhaps parents and children might find them useful.
The characters are interesting but rather one dimensional. They seem more caricatures rather than real characters you could sympathise with or root for and against. The story was not so much predictable as plodding. I didn't feel compelled to keep reading.
Overall, I must say I found the package neater than the content. The books are nicely designed beautifully illustrated. They seem like a fun idea but they come across just a tad too flat for me. If I were a parent I might check them out at the library rather than buy them new. That way you can see if you or your children are interested without investing anything more than time.