I don't trust CrowdSpring.com, they seem shady and have some really large projects but then access is so limited that you don't really know what's real and what's not. 99designs is a good company and I have a good history with them for logo designs but when I tried putting a larger project through their site the results are poor. It seems crowd sourcing produces some really great ideas but often leaves you with an inexperienced designer who can't finish your project. We were forced into finishing the project with a company that charged $125 per hour!!!... but they did a good job.
I'd have to disagree that the designers don't create designs that express the company's brand. If you're a lazy contest holder this is true but if you provide feedback often and guide the designers, the results are 10 times better than a design firm.
One company that looks promising is TheFinalPrint.com. They're offering "follow-up" "post production" services. Supposedly their design and programming staff will help you finalize print and web projects. Who knows what the result will be but I've opened a contest there. I hope they're able to "finalize" the project the way they claim.
I really love this design contest concept! Anyway, I think that's enough rambling from me...