I believe it depends on how well you can market yourself and your work. If you self-publish, then the marketing all falls on your shoulders. There are ways of doing this effectively, but it takes a good amount of time investment to do so.
The positive aspect of CreateSpace, is that your upfront costs are very negligible. I've seen many self publishing sites that want you to fork out over $1,000 before you even see a printed product. It might also be worth pointing out that CreateSpace is owned by Amazon.
Whichever way you choose, good luck!