I'd say that Manning is a worse hero than Assange, because Assange's faults (which all heroes need to have) are primarily personal, while Manning's, however well-intentioned, are based on acts done to impress a hacker idol.
On the villain side of the equation, it's pretty clearly the opposite – Manning is not trying to use his power for evil… And in fact, there are many good side-effects (perhaps even intentional ones). So, Manning ALSO sucks as a villain. Assange, on the other hand, clearly is again driven in large part by personal factors – both his belief that he is right, and in his leveraging of his position for his own advantage, at times even sexually so.
Thus, I will say the following: Bradley Manning is both a worse hero and villain, while Assange succeeds 'admirably' at both.
This also explains why Manning is currently jailed and no longer a real part of the "news cycle" except as a discussion point on the treatment of prisoners generally – he just isn't that interesting a "bad guy", or conversely as a "martyr" to the cause of transparency.