It completely depends on whether you're looking for employment or looking to outsource?
Elance, ODesk and other professional recruitment/freelancer sites are commodity-based competitively-driven races to the lowest possible $/hr rate. As an American professional, you're not making money here outsourcing your creative talents. Because people looking for resources here are looking for the cheapest option. And the dude in the Phillipines quoting $4/hr is always going to win.
Now, on the other hand, if you're interested in outsourcing any of your professional or personal life, or have a business idea and don't want to go broke giving it a try, these services may be perfect for you.