I think it depends on if you are up to do business work and the genre. Some musicians don't like to deal with the business side and just want to be creative. if you are up for doing the work though, you might be better off by yourself. This is where ethe genre comes into play though because if you are a pop artist and you think you can sell a lot if promoted right, then you might be better ewith a label especially a major one because they have that power to get you good widespread marketing. If you in a genre though that is not as popular, niche marketing might be better than widespread because there is a good chance you may get more fans by promoting yourself to only your niche because those are fans who like your style of music. With widespread marketing, yes it's good that you are reaching out to a lot of people, but a lot of people may not care.
http://www.billboard.com/biz/articles/news/digital-and-mobile/1566537/business-matters-relaunched-myspace-faces-uphill?