Feature wise, obsidian and dendron are fairly compatible and the obvious differences are what you already pointed out about vscode and open source.
I would say the main difference is that dendron has schemas and hierarichal lookup. backlinks are nice but you still need an organizational structure on top as you collect more notes. dendron provides that organizational structure as well as tooling (coming soon) to keep it managable (eg. refactoring hierarchies and filenames and updating the links everywhere)