Well I can safely say that Google have been very accurately screen rendering sites I have built with Angular JS. If you go to cached page in search results you can often see a screen render. This has been happening as long ago as late 2013 I think, at least for what it thinks are 'important' sites. It gradually got more common. Even though there was a screen render I had server rendering for fragment crawler requests, so I wouldn't know if it would have crawled JS too.