As a long time Realms fan, this is another one of those products that really shows what I hope the Dungeon Masters Guild can be used for.
The Moonshaes haven't gotten a lot of official love in a long time. This adventure uses what we know about the current state of the Moonshaes and has a suitable amount of fantasy Celtic feel to it, which is essentially the whole point of the Moonshaes.
While it's not an earthshatteringly new concept in adventures, it is very much what 5th edition had attempted to be thus far--a return to the solid feeling of D&D past, with a cleaned up presentation to make everything run more smoothly.
While I haven't run the adventure, from reading through it, it seems to be a good, solid, fun adventure that definitely feels like it belongs in the Moonshaes. If you remember the 3.5 days of Dungeon Magazine, I'd say that this feels more connected to the Moonshaes than most of the Forgotten Realms content that made it to the page in that magazine (barring adventures written by people like Eric Boyd, etc.)
My biggest complaint is that there is one encounter in the adventure that, if not handled well by the DM, could devolve into one of something similar to one of the less interesting skill challenges from 4th edition. That said, there is good context for the encounter, it just depends on how well the DM and the players get into describing the situation.
Looking forward to future installments of this series.