Source?
Me mostly.
But there have been comments questioning Snowden's claims by many in the media and people with background in the Intelligence community.
It's not that what he says are direct lies. Much of what he says is true but only to a limited extent.
He clearly exaggerates his ability to pluck information out of the NSA database. He claims for example that if he knew Obama's e-mail address he could read his mail. I don't think so. Nor could he listen into his recorded conversations. I don't believe all U.S. communications are collected. He infers they are. I think some are but most aren't. Time will tell who's right.