I would vote to convict, with no opinion on the sentence.
He broke the Law.
Might have been for a good cause, and I might agree with him as to the questionable legal, ethical and moral nature of the activities he exposed, but he (an IT contractor) does not get to be the arbiter of what is or is not the rightful place or activities of U.S. Intelligence.
The unsaid reality here is that the people who SHOULD have been the whistle-blowers here, the President and members of the Senate, all failed to do so or worse, support this policy to the fullest despite it's questionable nature regarding individual privacy rights and the Big Brother State.
That may make what Snowden did rightious, but that alone does not make it legal or his actions not due for appropriate repurcussions.
I'd vote to covict, because he is guilty, and I respect the law even in the Executive and Legislative branches do not. I'd give no opinion on sentence because thats not my place, but I'd root for a short/limited sentence.