Good question. My answer is that it has to be short, memorable, and easy to type in; plus be unique enough to be used in building a brand. If you're just going for small add revenue, a generic name, like weselldomains.com might generate substantial traffic without much effort and even do better than a uniquely branded domain in the short run. But in the long run, for actual market penetration it has to meet the qualifications I gave. A DIY home blogger might stumble on weselldomsins.com but to get a large portion of the market you need to sell an image of your company to consumers and that requires a brand and a domain that is easily associated with that brand.
As far as SEO goes. Google is who to impress and their algorithms get stronger and stronger. The question their proprietary algorithm and search engine spider bots are trying to accurately answer is, is this actually a webpage that people want to see at the top of their search results.
Short term: weselldomains.com is ranked better than a custom branded name. If they both launch on the same day.
Long term: wellselldomains.com will never compete with GoDaddy.com because they have penetrated the market and googles algorithm measures the internets actual interest of a site to determine its ranking.
In summery pick the unique URL thar matches your branding over a domain that has industry buzz words in it. Have pristine Programing throughout your website and provide relevant useful information then use all types of media (especially social i.e. Facebook, YouTube) to actually engage with your target and update with new content regularly. As real interest grows, traffic will follow and rankings will increase bringing more interest and traffic and further increasing your ranking.