It's worth noting, that googlebot does seem to do page renders with JS, though not as frequently and usually several days behind a non-js detected change. Bingbot definitely does, and this can even be seen in google analytics oddly enough (google doesn't seem to do any filtering for non-browser rendering).

Came to a lot of this knowledge when changing a url structure for a few hundred thousand pages (with permanent redirects in place)... the bing bot results on analytics were really surprising, and had to adjust filtering.