I can't speak to the GUI, just the TUI compared to tmux.

herdr is very flexible, but it shines when you are working with multiple projects, with multiple worktrees, and multiple agents within those projects.

1. herdr uses workspaces to help organize tabs. Conceptually, a workspace probably maps to a project, but it doesn't have to.

2. herdr has native worktree support, and can create a nested workspace per worktree with a keyboard or CLI command. It can check out worktrees for you

3. herdr identifies agents across tabs and workspaces and pulls them out into an extra navigational pane. It shows the status of those agents (e.g. idle, working, waiting, done), and can play a sound when they change state. This helps you track multiple agents across multiple projects and quickly switch to them when they need help without needing to remember "claude is running in space 2, tab 3"

4. herdr integrates with your agents, which can control herdr's UI and rename tabs based on their status.

5. All this is scriptable via the herdr CLI, and agents are very good at it. But it also has full mouse support, if you're new to multiplexers its very easy to start interacting with it.