@kolev great question.

1. First，I need to say: puer is created before browser-sync (more than one year).

2. puer provide some features that browser-sync that not supported(debugger, mock request, qrCode generate etc.)

but puer is not support the user-action Synchronization that browser-sync supported.

puer is aim to providing a simple foundation for common frontend workflow .

Thank you for posting this, after 20 minutes of trying to get Puer going I gave Browser Sync a go. Easier to install and the proxy setup worked first time. Also the documentation seems to be well laid out on Browser Syncs site with clear instructions and Gulp / Grunt examples... might give gulp a try soon.