So, what's your favorite way to handle configs when you've got systems spread out all over the place?

Hey everyone, I've been wrestling with managing application configurations across multiple services and environments lately. We started out using environment variables, but that's getting messy with secrets and frequent updates. I'm curious about what patterns or tools you've found effective for distributed configuration management. Are you using dedicated services like Consul or etcd, or do you have a different approach? What are the trade-offs you've encountered?