What's more important for an MVP and fundraising, functionality or pretty...?

In my studies of the W3 buildout, i see a lot of ideas raising a ton of funds with pretty web sites that [too me[ are just fancy bullet points of what they hope to achieve. Which would attract your attention more, that or a not so clean look but working, functioning model..? I would love to hear some answers from people in the @funding world also if possible.