> not just yaml toml and JSON

those are the formats available for configuring rotz itself; it's agnostic to the content of your actual dotfiles

Are your per-machine branches mostly distinct, or do they share a lot?

I use https://github.com/thoughtbot/rcm and I find my dotfiles share _quite a bit_ in some respects (e.g. neovim config) but are drastically different in others (SSH config as one example) -- keeping things synced _across_ branches sounds very difficult. rcm handles this well, without branches, IMO.

> I just have a git repo with a branch for every machine.

Aren't you supposed to "not" commit secrets/sensitive values to git repos as "best practice"?

I also don't get these, but for another reason: why write a dotfiles-specific configuration management tool with templating, conditions and all of that when we already have proper SCMs like salt or ansible that perfectly scale down to a single user and a small number of configs, but are still orders of magnitude more powerful when you need it.