Owned it for years, never got around to trying it. Recently I played it recently and I must say I am quite pleased!
As a New Englander myself, the more ocean based scenery and setting are something I was really looking forward to seeing in Fallout 4, only to be largely disappointed., this DLC is primarily focused around these things, so thats a bonus for me.
I also am a fan of the Children of Atom, so I was happy to see they are one of the three major factions on display here. The Children of Atom cosmetics and items are very fine indeed, they also have radiation infused weaponry/firearms, so if you ever wanted to do a modded Ghoul play-through or something, this DLC is practically made for it.
At first I was worried when I noticed the main story thread of the DLC revolves around Synths, but I think it was handled very well. I didn't find myself rolling my eyes at any of the factions, the pacing is good, the missions aren't tedious and primarily exists to help guide the player to the corners of the sizable DLC island map.
There are multiple endings to this DLC, it seems like. I focused on a peaceful route, siding with Far Harbor, as I didn't mind any of the factions in particular and they all have their own reasons for wanting dominion over the island. But there are more particular paths for repeat play-throughs to go down.
Its easy to see why this DLC is so highly rated, the team in charge of this should of been allowed to design the base game.
I liked the aesthetic, the tone, the items, the factions, the creatures, especially the Giant Hermit Crabs and Radchickens!
Overall, I rate it a 5/6!
A nice break from the base game and then some, a refined DLC worth your time, at least once, would play it again in any future play-through!