Sanders has been implicitly accusing Hillary of accepting bribes via campaign donations. He's accused her of "not being a progressive". (lol)When has Bernie ever talked shit on Hilary? Usually he's been pretty tame when it comes to any kind of attacks.
Mostly it's been Hilary doing the slinging... Though things can change... I just don't see Bernie himself personally doing that.
Clinton has been trying to keep the attacks focused on Sanders' policy positions. He's come right after her character. The two are not equivalent.