I'm no Musk fanboy and this isn't meant to be a defense of Musk, but in my opinion, Musk exaggerates and over promises. He'll say intentionally vague things and let people fill in the blanks and not correct them when they are wrong. It's all a little slimy and grey, but there's usually at least a modicum of truth to the things he says or he at least believes what he's saying at the time he says it.

From what I've heard recently Nikola just seems like straight up lies and fraud from trying to piggy back on the success of Tesla.

Neither are good, but one is much worse in my opinion.