Pros:

• Provides detailed information on fey NPCs and statblocks as well as new fey races, faerie-themed subclasses, and magic items of the feywild.
• Faerie backgrounds and characters are drawn from past D&D editions as well as classic mythology stories, such as Irish myths, King Arthur, and William Shakespeare.
• Legacy items that unlock new abilities as you level up are a fantastic concept that deserves its own DMs Guild supplement.

Cons:

• The fey subclasses are the least interesting but take up the most amount of space; many subclasses already had solid fey-themed versions, like the Warlock and Paladin.

Full Review: https://roguewatson.com/2019/02/06/-
dms-guild-review-myrddins-guide-to-faerie/

Video Review: https://www.youtube.com/watch?v=4C0jhuNCKYw