Superpowers + worktrees works really well for me. Superpowers works well at building comprehensive plans for implementing large features or refactors, and asks the questions up front, and then worktrees provide a safe place to actually perform that work.

It's not perfect; I've had some issues with Claude Code forgetting where it did things ("oh... it's not working because I'm not in the right directory"). I think it needs some architectural tweaks to function more reliably.