The most detailed, nuanced account of Assange I've seen is this one[0] by Andrew O'Hagan (an author hired to ghostwrite Assange's autobiography who spent a year or so in and out of his orbit). And it's hard to square that account with the image of Assange as a journalist who's being persecuted for the truths he's shared.
Though O'Hagan is sympathetic in many ways he doesn't sugarcoat anything, and I came away with the impression that Assange is the author of a great deal of his own woes. (Among other things, much of the account involves Assange lying pretty incessantly, even to his closest allies about petty dramas, so I now find it hard to take anything he's said at face value.)
[0] https://www.lrb.co.uk/the-paper/v36/n05/andrew-o-hagan/ghost...
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Edit to add: there's a quoted exchange in the account, which now springs to mind every time I hear about Assange.
> There are few subjects on which Julian would be reluctant to take what you might call a paternalistic position, but over Snowden, whom he’s never met but has chatted with and feels largely responsible for, he expressed a kind of irritable admiration. "Just how good is he?" I asked.
> "He’s number nine," he said.
> "In the world? Among computer hackers? And where are you?"
> "I’m number three."