In my, ahem, limited experience, it seems like a well-constructed site is very much needed. Most have only the most rudimentary, earlier-this-decade, styles of filtering.
I'm certainly no expert, but the free *Tube sites I've seen are pretty ghetto. Maybe it's better once you start paying, but for instance I'm always seeing stuff I'd rather not in the listings for whatever category. It might be like dating sites, though, where the business model is to keep you on the site irrespective of why you're there, so there's no incentive to make things easy to find.
