Chrome's DevTools handles developing large unbundled webapps better. When your loader is reaching to the fs for thousands of source files for a single page load, Chrome performs significantly better than Firefox. Same goes for Ctrl+P jumping to files and debugging performance.

It's gotten a lot better over the last two years, especially when FF DevTools got support for source maps and TypeScript debugging, but it still lags enough to keep me using Chrome for my job, Firefox at home.