I really liked Tmux and Zellij for the time being, but Herdr does it all so much better out of the box when it comes to agentic coding. I haven't found something I can do with tmux/zellij but can't do with herdr.
I'm mostly using it now because it integrates with ssh while still supporting image paste. I also use it via it's json API for a harness I'm working on which is agent agnostic.
I do expect I'll move off it if it becomes hostile and another tool takes it's place.
As a result I still run sessions and processes I really don’t want to lose inside tmux, nested inside herdr. Tmux never crashes.