Its not terrible, but its not really great, either. I do like a clean design, but there is something that feels sort of neutered about the front page. I can't properly explain it, and its not just because its different and new. The front page doesn't feel like a proper portal into the site that Renderosity is. I think it could be more inviting, and maybe more colorful. While some people are talking about the splashes of color in buttons, the site itself is still mostly dark grey.

Mobile shouldn't be a huge concern. It is pretty easy to make a site work on mobile, and more over, mobile processors are more powerful than ever. People have more power in their phones than Windows XP based systems of a decade or so ago. The only concern for mobile should be data use and formatting. But this is an art site, you kind of need to show pictures, so there's no way around that other than compressing pictures for mobile.