i like plantuml. however, i think it has more complicated syntax. if i mistype something, i often get an error.

gleek.io is partly based on mermaid, it has its own UI and extra features like saving diagrams on its servers, Git integration, link sharing, integration with Azure DevOps, integration with Confluence is on the way, etc.

i don't see the company going down the drain, it is only one of our projects and not so expensive to maintain. the diagrams are saved on the servers and you can export them in different formats.