That's a great portfolio, a very focused and intentional portfolio.

I'll be honest. I'm pretty astonished, solely from the things Unreal has put out recently.

I'm not entirely sure where Artstation fits in though, it seems to be a portfolio website for artists more than a marketplace. It has incredible potential though, if I owned the company I would turn it more into a social network, more chat/communication/group features rather than use it for its assets. I think its only serious competitor is DeviantArt and that website is well, how shall I say it, full of deviants.