Brother, Georgetown's is the most prestigious of the foreign service programs. It's no coincidence that some applicants were accepted into GWU/Harvard HKS/Columbia SIPA/Korbel but were not accepted into SSP.
You are not at a real disadvantage in any foreign service program, but SSP/SFS is Georgetown's flagship (like the Law school is Harvard's flagship).
Therefore, the advantage of SSP IS the prestige, the curriculum, and the professor cadre. SSP averages 95% job placement for its students in both the private and public sectors.
Proximity is another key advantage, which SSP shares with GWU. If your intent is to land a job connected to the beltway, there's no better place to do that than in the beltway.