They are quite similar, PlantUML has support for more types of diagrams than mermaid (such as network diagram), but IMO PlantUML is "messier" to write, I find M

They are quite similar, PlantUML has support for more types of diagrams than mermaid (such as network diagram), but IMO PlantUML is "messier" to write, I find Mermaid more elegant in writing diagrams.