I really like what I'm reading in Ruins of the Lost Realm. The book is very useful for building a campaign, and it gives me hope that further releases (especially Moria) will be equally good.
If I had one criticism it is the choice to include certain concepts that are lifted straight out of our own history, legends and myths. This is very immersion-breaking, especially at our table. Examples would be "The Green Knight" (pg 84) and even calling an NPC "Ivoch the Boneless" (pg 45), who is even the son of a mighty chieftain. Middle-earth should be inspired by such things, not copy them, I think.
Each group is different, of course, but for our group, such "transplantations" will be so immersion-breaking that they're not useable.
Well, it could be worse. I remember an old Savage Worlds fantasy RPG that was inspired by Norse myth - but they called gods Odin, Loki, Fenris and such! Creativity is better than just copying.