Had a peek earlier today (the vid too)… looks pretty awesome man I must say!.. Anything sci-fi + video game = has my attention 
I personally haven’t tried Pioneer yet but it seems like the watermarking is only on Scene renders, unfortunately in the case of making Skies, that could be an issue. But the RenderUp pack is only about 70 bucks and removes the watermark + adds the full rendering ability of the $1400 version of Vue right into Pioneer for 500% less cost lol. xStream is really only worth getting if you want to use Vue as a plugin with other CAD software, which is the reason I bought it in the first place years ago, haven’t had much use for the ‘xStream’ side of things for a while now, but always good to have the Vue renderer handy when I don’t want to wrestle with Maya or Max’s internal renderers (I honestly prefer Vue over both of them by a long shot).
I also love how easy it is to slap a quick [camera] animation together in Vue, their animation *wizard *lives up to it’s name 