I agonised over reading this manga. Typically I binge, and I'll finish a series in a day or two, but I spent at least two weeks reading Palace Meidi, spending as much time on each chapter as I might a volume in other circumstances.
The attention to detail in Palace Meidi is astounding. I can only imagine the amount of thought and research the author put into each chapter. It creates a vivid image of life in the palace during the Meiji restoration, and the art is exceptional. The scanlators should also get a lot of credit, as they provide many margin notes that provide additional information for those not familiar with the period.
The story is not altogether unique (actually it's a bit cliched) - forbidden love between individuals of different social standing. It is really the exposition, art, and writing that make this manga special.
My only real criticisms of Palace Meidi are that the characters often come across as quite stiff and difficult to understand, though this could be because most dialog takes place in formal social settings. Also, the foreshadowing is really ugly and unnecessary, and often disrupts the flow of the narrative by allowing readers to reliably predict what will happen. Don't end a chapter with "but little did they know what would happen next..." when it's straightforward to predict how things could go wrong. Actually, just don't do it at all, the only thing it does is diffuse any tension by letting the reader know something bad is definitely going to happen (rather than only possibly going to happen).