I'm not so sure. First, setting aside politics (where I align closer to Cruz than to Sanders), Cruz is so sanctimonious and stuffy that I question his authenticity. He's not a blatant fraud like Hillary Clinton is, but I don't sense that the guy you see on TV is particularly similar to the Ted Cruz you'd see lounging around the house with his nuts hanging out the bottom of his shorts. I think the Sanders you see on TV is basically the real guy.
Second, I think Cruz's strategy is far more calculated, disciplined, and methodical, and I think he's tailoring his rhetoric to that strategy. He did the same thing to win his Senate seat. I don't see anything like that from Sanders. I see a guy who's got his own message that hasn't changed much in 40 years basically winging it with little regard for the optics. On the more negative side, I think he's less careful. For example, Cruz would never get into something like data problem Sanders is in, and if he did, he'd never have the humility to say he was sorry or admit he screwed up.