In my view we have had too long a period where Snowden is the one telling the truth and the gov's have been outright lying and then caught out. When that happens it doesnt matter if the intelligence agencies are telling the truth nor if Snowden decides to turn KGB, who can believe it?
Snowden gained credibility very quickly and the intelligence agencies lost it quickly. Snowden appears to be trying to do something for the public good with very careful actions. The intelligence agencies seem to be trying to store the dirty secrets of everyone to use at will and to damage Snowden's reputation.
How would we be able to tell if the data has been compromised, how and who by? How would we know if it contained anything dangerous to anyone? So in this uninformed position who are we more likely to believe?