International Sourcing Companies

Thought I would do a little bit of 'Crowdsourcing' with regards to Sourcing Agents. Every week I get at least 5-10 emails from people who run or are involved with Sourcing Services, all have a differing set of services ranging from simple vendor identification, to full supply chain management. Personally I am inclined to turn down such services because the companies are always based in China, India, South America etc, as you would expect, but they have nothing in their customer locations. Which means everything is done electronically or by conference call and a lot gets missed, misunderstood or doesn't even get communicated. What is your experience with them, why do you use them, or even why you don't use them? What one thing could Sourcing Agents change which would make you consider using them, or make it easier to use them? Thanks for sharing