Fantastic Beasts and Where to Find Them by J.K. Rowling
Struck me as weak. The invented monsters are gags more than intriguing, and the strict limit (only 73 species? what, no room for jackalopes?) meant that there were not so many of the folkloric ones. Though she did manage to get quite of a few of the more obscure ones.
The Tales of Beedle the Bard
I bounced off this one. Hard. Starting with the intro. We have the assertions that Muggle fairy tales are all hapless heroines. (grumble, grumble, grumble, GROUSE.) Also that magic is a solution in Muggle tales but not in wizard ones. Well, why not? After all, the classic fairy tale trope of an animal that feeds a poor put-upon stepchild is as impossible in the wizardly world as the Muggle one. And all you have to do to keep your stepchild helpless is break, take away, or never get a wand. And just knowing magic doesn't mean you know where to apply it, so you might need the talking animals' advice.
But then I did plug into some tales, and the tales do not come across as folk tales but as heavily literary. It's hard to catch the authentic folk note, but like many others, this doesn't have it. And I could not get into them.