Hi Wesley,
I am new here, but I believe I can answer this one. As of the end of 2012, according to Google's Matt Cutts, brands using multiple subdomains will no longer receive the SERP advantage and subdomains and subdirectories are now both classified as internal links. Cutt's is recommending that you choose the structure that is easiest for you to maintain. Here is the YouTube video for more explanation: http://www.youtube.com/watch?v=_MswMYk05tk
I hope that answers your question.
Thanks,
Christine DeGraff