Currently the builder erases XML comments within the UXML file -- very annoying when one is experimenting with interfaces
If you going hand-written you have no choice but too stay within that realm, either full handwritten or full UIBuilder. UIBuilder rewrites the whole file and will also wipe out any custom formatting - or will even replace `path` with `src` in many cases. Unfortunatly one can only wish UIBuilder would function like Dreamweaver.