the first one is about phantomjs crashing and many many other scary sounding issues you wouldn't have if you've used just a regular browser with Xvfb.
you can't really be sure unless you've literally run a test on the colorful variety of websites in the wild. You need a huge development and quality assurance team. You also need a way for a large crowd of people to test your browser and send back useful reports automatically whenever it crashes.
1470 open issues
the first one is about phantomjs crashing and many many other scary sounding issues you wouldn't have if you've used just a regular browser with Xvfb.
you can't really be sure unless you've literally run a test on the colorful variety of websites in the wild. You need a huge development and quality assurance team. You also need a way for a large crowd of people to test your browser and send back useful reports automatically whenever it crashes.