I regularly worked with Elon while a part of his electric car company - Tesla. At first, I hesitated to write a response, but as I thought about what I'd say, it was overwhelmingly positive. So here we go:
Amazing visionary: During one of my first meetings with Elon, he made a request that I thought, frankly, was crazy. I asked my coworkers after the meeting if we really were going to do that. I was told "if Elon says to do it, we do it. Give it time, you'll understand." Sure enough, each seemingly crazy request was grounded in a logic only Elon understood at the time. But we trusted him and I ultimately found myself in agreement - sometimes it took six months or longer to get there.
Crazy smart: No matter how tired he was or how many times he'd travelled back and forth across the country in the last few days, or how many fire-drills were running simultaneously, he understood what you were saying. He'd sit there with his famous "uh huh" and a head nod, acknowledging that he understood. And his followup questions were target and relevant.
No tolerance for bullshit: When we met with Elon, we were prepared. Because if you weren't, he'd let you know it. If he asked a reasonable follow up question and you weren't prepared with an answer, well, good luck... Our discussions were efficient, to the point, and based in fact. He expected to see progress.
Execution: You always need to be making progress. And if you weren't, you needed to escalate or find a solution to the deadlock. It was unacceptable to keep problems to yourself.
Willingness to help us get "unstuck": Sometimes we'd get stuck dealing with a vendor or making a decision across departments. He often tell us "Get me on the phone with the CEO of <insert company here>. I don't care what the problem is. We need it resolved now." Or if it was a company decision, he'd just assert the answer and we'd move on.
No fear of making the hard decisions: When you're in the trenches working on a hard problem, it's natural to convince yourself it can't be done. You start to compromise. Elon had no tolerance for this and rightly so. We'd exceed our goals, because we had to. It was how the company would survive and he reminded us of this if we drifted too far. If market conditions prompted us to change course, we would. If we needed his sign off on a large project or spend, as long as we did our homework, it was logical, and we laid out a plan, he'd be ok discussing. But he'd often send us back to rethink the proposal if it didn't jive. He wasn't afraid to spend money when needed.
Drive to do the "right thing": It doesn't matter what the status quo is. Never tell Elon "well, that's how we did it at Ford." He pushed us to always do the right thing for the customer. Making money is important to keep the company running, but it's not the most important thing. He pushed us to make a great product that is uncompromised in solving the needs of our customers, even if it goes against the automotive norm and the critics on Wall Street.
Hands on: We'd frequently see him looking at a CAD drawing at an engineer's desk. He has all vehicle engineering changes first installed on his Model S or Roadster so he could personally approve it before it goes to customers. His expectations were high. If we couldn't meet them, then he'd rather scrap the work than build a mediocre product. He wasn't afraid to get down in the details.
Personality: Sometimes he'd be in a really good mood. Sometimes not. But for the most part, I found him to be easy to get along with and supportive when progress was being made. But if too many bad meetings took place in a row, then beware... And be careful disagreeing with him. He frequently knew more than we expected, so it was risky to tell him he was wrong because he might not be.
All in all, Elon has a dedicated and loyal following. It's because we believe he knows what he's doing. He doesn't inspire us through big speeches and eloquently written emails. He focuses on getting work done, executing to plan, and driving positive change. And nobody at Tesla had more skin in the game than Elon. I'd choose to follow him over any big talker with empty promises. His push to improve the auto industry is refreshing. His dedication to improving the quality of the world we live in is inspiring. It's a rarity in the business world. I hope we each do our part in making his vision a reality, as it's ultimately in our best interest.
Edit - Response to comments:
Negatives of working with Elon: Very demanding, he's not afraid to fire poor performers, you do what he says (if you disagree, be thoughtful about whether it's worth the risk, most of the time it's not...), not everyone works well with such a strong authoritative figure, most people are scared of him, his ambition can be exhausting - there's always another huge problem we have to solve, long hours.
Why post anonymously: So I could write the above paragraph.