I've stuck with 2016 xStream and only know a few things about the later subscription-only version.
- Vue still imports scenes from Poser. If it will continue to load a Poser 12 scene, when Poser 12 final is released... who can say?
- The UI has changed quite a lot.
- Plant Factory now seems to come along with Vue(?).
- Like Daz Studio, Vue R5 (Subscription) won't run on the current Apple Mac OS ('Big Sur').
- It has a new module that enables you to grab a terrain from any part of the Earth, make it a mesh and drop a satellite texture on it. Quite how hi-res either the mesh or the photo is, I don't know.
I'd also be interested to find a list of new post-subscription additions and speed-ups (if any).
Learn the Secrets of Poser 11 and Line-art Filters.