[nader]

When you're looking at sites like reddit, hacker news and others which don't have a great/nicely looking user interface you would think it's not that important. But I think it also depends on the target group. For consumer-oriented, less internet savy people websites it is essential to have an appealing professional looking design, great usability, ease-of-use and optimised text.

So to answer your question I would release an early messier version to a closed group of beta users, ie. early adopters but before pushing onto the mass market I'd clean it up.