Headless node.js javascript browser with screenshot capability?
I doubt you will find anything that is going to work as well as phantomjs. I would just treat the rendering as an async backend process and execute phantom in a subprocess from your main node.js process and call it a day. Rendering a web page is HARD, and since phantom is based on WebKit, it can actually do it. I don't think there will ever be a node library that can render a web page to a graphic file that isn't built upon an existing browser rendering engine. But maybe one day phantomjs will integrate more seamlessly with node.
Try nightmare, it uses the electron, it is way faster than phantomjs, and it's API easy and uses modern ES6 javascript.
This might look like a solution with a little bit overhead...
You can use the Mozilla Firefox with the MozRepl plugin. Basically this plugin gives you a telnet port to your Firefox which allows you to control the browser from the outside. You can open URLs, take screenshots, etc.Running the Firefox with the Xvfb server will run it in headless mode.
Now you just have to control the browser from the outside with node.js. I've seen a few examples where someone has implemented a http alike interface inside the chrome.js of Firefox. So you can run a http command to get a screenshot. You can then use http calls from node.js. This might look strange, it actually is but might work well for you.
I'm running a slightly modified version in production with Perl Mojolicious in async mode to trigger the screenshots. However, there is a small problem. When plugins are required they do work, however Flash usually gets activated when it's in the visible area, this won't happen so movies/flash things might not get initialized.