When comparing NW.js (w/xvfb) vs Zombie.js, the Slant community recommends NW.js (w/xvfb) for most people. In the question“What are the best headless browsers for testing?” NW.js (w/xvfb) is ranked 3rd while Zombie.js is ranked 5th. The most important reason people chose NW.js (w/xvfb) is:
Ranked in these QuestionsQuestion Ranking
Pro Node integration
The integration of Node with the DOM in NW.js opens up a number of new options in how your headless testing workflow can be facilitated.
Pro NaCl support/integration
Access to the Native Client offers up more options in implementing your testing workflow.
Pro Runs on Node.js
Pro Fully featured api based interaction and assertion
The way the api is built makes it very easy to add to your test framework.
Pro Claims to be "Insanely Fast"
Con xvfb Requirement (for now)
Headless is on the NW.js roadmap, but for now xvfb is necessary to get going. The community has done the work and you can find the details here.
Con Support has waned
As of August 19, 2016, Zombie hasn't received a commit since January 2016. Issues get comments like "patch welcome".
Con Stale documentation
Full API documentation has been missing since the start, making it frustrating to use.
Con Fails to load many sites
Con No screen-shot
As it doesn't render the page, you cannot get a screenshot to for testing or reporting test failures.