There are two views of former Google VP and new Yahoo CEO Marissa Mayer in the industry.

One is that she is a brand name product leader who played a crucial role in helping Google develop its most valuable business—search—and then went on to guide the development of several other popular products including Gmail, Google Maps, and Google News.

This view is the one that was all over the Internet yesterday.

For example:

This view's popularity is the reason Yahoo's board is thrilled to have landed Mayer as its CEO. The board believes it will help her recruit talent into the company. (It probably will.)

The other view, more common amongst long-time Googlers, is that Mayer is a publicity-craving, lucky early Googler, whose public persona outstripped her actual authority and power at the company, where she was once a rising star—thanks to a bullying managerial style—but had become marginalized over the past couple of years.

Yesterday we spoke at length on the phone with a former Google executive who worked with Mayer and says she and others like her have this view.

She told us twice: "This is a great day for Google, and a nail in the coffin for Yahoo."

This source described an executive who "will work harder than anyone" and "is smarter than 99 percent of the people," but "can't scale herself" and "doesn't understand managing any other way than intimidation or humiliation."

This source says that when she worked with Mayer at Google, Mayer "was just a nightmare"—someone who had her own publicist, forced underlings to sign customized NDAs, and maintained "a shadow HR staff and a shadow recruiting staff just for her team."

"No one understood why she had the power that she had, except that she will literally work 24 hours a day, 7 days a week."

"She used to make people line up outside of her office, sit on couches and sign up with office hours with her. Then everybody had to publicly sit outside her office and she would see people in five minute increments. She would make VPs at Google wait for her. It's like you've got to be kidding."

This source says that for a time, Mayer attended executive coaching lessons with Bill Campbell, but that the gossip is he refused to keep teaching her because she was unreceptive to feedback. Another source confirms a falling out between Campbell and Mayer, but doesn't know why it happened.

So which view is more accurate? Is Marissa Mayer Google's golden girl? Or a workaholic tyrant with an uncomfortable management style?

Marissa Mayer has "matured" in her leadership style, says a source close to her OLIVER LANG/Getty Images We found a source with a particularly interesting answer to this question.

This person worked closely with Mayer over the years at Google.

This person's answer is that Mayer is, or rather has been, both.

This source is now a "huge fan" of Mayer's, but says "I used to not be."

"I honestly thought she was crazy [during her early years at Google]."

This person says that Mayer used to be a polarizing executive at Google because of quirks—like how she managed her underlings and fought political battles with other top executives—but that "she is really not so much any more."

"She is 37 now, and she was in her late 20s less than a decade ago. Like all people, she matured and learned. It's not fair to cast her in the mold of when she was 28 or 29. She is a different person and leader now."

Mayer has, for example, stopped asking other executives to line up outside her office for five minute meetings during office hours.

"One of her flaws at Google is that she was too tough with her colleagues in the early years, and these people have memories like elephants."

"I think there was a time that she was more insecure, but she has really matured over the years."

This source says that doesn't mean Mayer isn't still tough."She is strong-willed and has strong opinions. She is willing to say what she believes to be true, which can make her unpopular."

But, says this source, there are lots of people at Google who want to work for her. For example, there's the story of Jen Fitzpatrick. Fitzpatrick went on maternity leave while working for Mayer. When she came back, she had a new boss. Google had gone through a massive re-org, and Mayer had been moved to a different organization. Mayer then asked Fitzpatrick to join her new team. If Mayer was a tyrant, this would have been a great opportunity for Fitzpatrick to say no, and escape. But she didn't; she joined Mayer's staff.

"She has her flaws, but she has really grown through the years," says the source.

It seems entirely clear to us that Mayer has alienated some people who have worked with her over the years—and that these people probably have plenty of good reason to be chaffed.

But it also seems clear that much of this alienation stems from the fact that Mayer has always worked harder than any of her colleagues and her reports—and has often been smarter than both—but has not always known how to deal with this disparity in a productive way.

According to a source we trust, she has matured and learned to deal with this issue.

In this particular way, Mayer reminds us of another famous Silicon Valley executive who alienated lots of people who worked for him: Steve Jobs.

Funny enough, the anti-Mayer source we quote above also sees the parallel, though she didn't phrase it very flatteringly in an email.

"Marissa is a nightmare of a human being, but she gets things done. If being a good person were necessary to be a CEO, we wouldn't have Apple ... and lots of other CEO roles would be empty."

Before the comparisons between Mayer and Jobs go much further, of course, Mayer has to do what Jobs did with Apple: turn around a once-great company that has stumbled to a point of near irrelevancy.

If Mayer can do that—and lots of smart industry people think she can—the last thing you'll read about her is how she keeps her office hours or whose feelings she hurts in the process.

Briefed on details and quotes from this story, Mayer and Yahoo declined to comment.

Related: The Impressive Career Of Yahoo's New CEO, Marissa Mayer