I've been doing Single Page Application (SPA) since 2010 using Google Web Tookit (GWT) with GWT Platform (GWTP) as framework. One of the most annoying things in SPAs in my experience is its inability to be rendered by Googlebots. That means your application or website will never appear in google search i.e. unless you do some extra tricks. You are left to be the one to render the SPA to its HTML form if you want google to index your SPA's pages.
Google provided a means for SPAs to be indexed in google search but the rendering is delegated to the SPAs whereas traditional HTML is rendered by googlebots on its servers. To be indexed, one must implement AJAX crawling specification. I use to implement my own, using HtmlUnit, however, it's quite hard to keep up with its version upgrades and dependencies. Most of the time there are quirks rendering problems which left me feeling unsatisfied with how it was seen by Googlebots vs how it was seen by the users.
Middle of this year I was fed up with my own AJAX rendering in-house code that I switch to just paying up Prerender.io $15 per month just so I won't have to deal with problematic AJAX quirky rendering everytime I upgrade versions and dependencies.
Now, I just learned that Google will be rolling out their own renderer for AJAX crawling this second quarter of 2018! My God, it's about time. I just tried it using Google webmaster "Fetch as Google" tool and the SPA page was rendered properly. The immediate impact of this to all single page applications and websites is that we don't have to subscribe and pay to 3rd party vendors just to render each SPA page to HTML (so that it can be digested by Googlebots) nor maintain an in-house AJAX renderer to comply with the AJAX crawling specification to ensure that pages are listed in Google.
Here's a comment from Prerender.io in YCombinator news after Google's annoucement AJAX crawling support.
I'll still be using Prerender.io perhaps up to 2nd quarter of 2018 just to make sure I won't lose any indexed pages but after that I'm going to be $15 richer per month and worry-free in terms of indexability/crawlability everytime we have new website/app version release!