I've met a lot of different ENTJs.
I really can't find one uniform opinion about this type, but that's like most all types, really.
I've read that they like to give out orders even when there's no reason to do so. My Dad, who is an ENTJ (albeit only barely a thinker) does this all the time. If I was opening a door, he might direct me to "Open the door." I was always thinking, "What do you think I'm doing here?" He loves to direct people, even if they don't need it. He always evaluates my every move, usually negatively. I think you could argue he has some unhealthy ENTJ traits. Now that I understand him better, I know that's just his way of trying to make the best of a situation. However, it still can be bothersome. He is quite overbearing at times. He just can't stop doing it; I've tried to help him stop but he isn't capable. He knows this, and has trouble tolerating that I often don't do what he says. So, it sadly becomes a mutual lack of tolerance. He isn't especially scary though; when he wants to be he could be, but he's just a mad director, not an intimidator.
There are other ENTJs I've met in life who fit the "scary" image and scare the crap out of certain people. I understand why some find them scary, but I don't personally find them to be that way because I tend to see through their fascades. I think only unhealthy ENTJs rely heavily on intimidation of others to promote themselves. I've met a few of these ENTJs. They tend to be neutral with me, but occasionally I meet one that doesn't like me. When this happens, our personalities repel each other and interaction becomes either minimal or completely non-existant. When I see how they treat others, though, I'm glad it's this way. Not that unhealthy INFJs are any better, by any means. But we're talking about ENTJs here.
The ENTJs I'm really cool with tend to not fit the stereotypical unhealthy images. They embody the positive traits of the personality type such as reliability, honesty, integrity and intelligence, without being overbearing. It's kind of how good INTJs are; the unhealthy ones are arrogant and elitest sometimes, but the healthy ones care for others and help them. They just tend to do it because they "think" it's the right thing, not because they "feel" it's the right thing. Honestly, it doesn't matter if thinking or feeling triggers your decisions as long as you're making the right decisions.