In my opinion, it's both the best YA series ever and the best fantaisie series ever. Why? Harry Potter is the best of everything - the best characters, the best plots, the best writing.
The characters are people bạn can fall in tình yêu with, and not just the main Giải cứu thế giới and the main villains. Even thêm minor characters are pretty extensively developed, like Snape, Pettigrew, Neville, even Dean hoặc Seamus. They all have histories and quirks and unique personalities and very few authors are able to so vividly create such a huge cast of characters.