Ramanujan is an interesting comparison. He was an outstanding mathematician, but it feels like his prowess came from a deep love of math and concomitant time spent on it. There's an anecdote somewhere about child Ramanujan working his way through thousands of elementary lemmas for fun, and I wonder if this gave him the almost occult intuitive ability reported by his collaborators. The stories about him have a tone of awe, but not fear.

In some contrast, von Neumann seems to have been able to take his enormous fluid intelligence and speed and apply it to pretty much whatever problem he decided, and he did it across many areas, including non-scientific ones. The stories about him are tinged with a little unease, and it's a little harder to see the human underneath his achievements.