There is no a clear winner in this battle because both ways of promotion have their own benefits. Basically, if you have got a long domain name like freesexygirlscams.com or live-girls-porn.com, then it is better to send your traffic directly to the sponsor, because most of the users will not trust such a site and they will not give their private information.

But if you have got a nice niche name like ebonywebcams.com or something like that, then it is definitely more to build a white label on it because it is easy to remember and it does look professional. Another advantage of the white labels over sponsors is that people will bookmark your website if they like it and they will keep coming back to your place.