Far Harbor is fine. The island is a nice change of pace from from the Commonwealth and the actually nuanced factional politics called to mind New Vegas in a nice way. That being said, the island is pretty homogenous and samey all over, and aside from a pretty neat Vault quest, a lot of the quest design outside of the main quest falls into the same trappings of "go here, clear the enemies, return." Additionally the more complicated dialogue-heavy quests in the critical path really expose how flawed the dialogue system is in 4.

Overall, it's just kinda fine.