Germany's 11-inch gun was a cruiser weapon, not a battleship equal

Was the German 11-inch gun superior to the heavy guns used by other navies?

No. It was formidable in the cruiser category but did not match the true capital-ship guns of the period.

The weapon sat between ordinary cruiser armament and modern battleship guns. It could compare with 12-inch weapons and dominate eight-inch cruisers at range. It could not deliver the performance of British 14- and 15-inch weapons or contemporary 16-inch guns. The gun made a raiding cruiser dangerous but left a battleship-sized Scharnhorst underarmed. It was an effective weapon used in an unsuitable application.