It is a stunner. I do see how you can argue that it's undergraded. What I notice after looking at hundreds of these types of coins is that the Germans relied on expressiveness rather than detail in depicting the hair of the rulers. The head detail is often quite shallow and nearly one-dimensional in appearance, even on mint state coins. Seeing that much detail in the highest point of the obverse would lead me to call it AU-53. The reverse shows as an XF-48, so that might take my final grade down to AU-50--but the one remaining factor would be the luster. This is one coin where, in my opinion, the toning had the effect of bringing the grade down. If this coin were white and shiny (uncleaned), I'd bet it would be in an AU-55 holder, but so what? It looks better this way.