For a long time, David Alison was a Mac hater. In fact, one of the avatars he used was the face of actor John Hodgman, the PC guy in Apple's 'Get a Mac' ads. As a software developer, he was heavily invested in and committed to Windows. While he had been a longtime iPod fan, it hadn't been enough to get him to switch.

But then last year his friends started buying iPhones and making the switch – "guys like me, who didn't really care for Macs". And when the latest Windows operating system, Vista, came out, Alison said: "It didn't do anything for me. The very initial version was really a mess."

So he went to an Apple store. The clean, simple and friendly experience convinced him it was time to consider a Mac, and now, six months after his first MacBook purchase, he has added a desktop Mac Pro and another MacBook Pro.

Alison's experience is not unusual. Blog after blog chronicles the move from Windows to Mac operating systems – and more than a few were precipitated by Microsoft's Vista. And with the final door having closed on XP – Microsoft is no longer allowing manufacturers to sell new computers pre-loaded with XP – it's possible user frustration could translate to even more sales for Mac.

Analysts, however, agree that while Vista's poor public reception – deserved or not – has done little to spur PC sales, they also caution that it's not the only factor driving Mac's increasing market share.

"Apple has told a good story, created good products and created a good [retail] experience for people to buy Macs," said Jupiter Research analyst Michael Gartenberg. However, he added: "The whole Vista launch was such a debacle, and that has helped Apple."

The launch "debacle" he's referring to is the January 2007 debut of Vista, which was not only delayed by more than six months, but also was "buggy", with compatibility problems and uneven quality noted in many early reviewers' and users' opinions. And the estimated $500 million (Dh 1,836m) spent on the launch seemed only to draw a bull's-eye around the operating system.

Indeed, half of the eight "Get a Mac" ads Apple and its agency TBWA created so far this year mention Vista. And the latest, "Sad Song", has the PC guy singing The Vista Blues about how Vista is causing people to leave him for Mac.

However, NPD Group analyst Steve Baker doesn't think that's exactly true. He said mainstream consumers don't think too much about operating systems when they buy a computer, and people who do talk about the negatives of Vista versus Mac are "talking to each other". Baker said he believes that as the market expands, people are simply buying Macs as a second or third computer.

"If Vista was such a disaster with consumers, that would have shown through in sales, and that didn't happen," he said. "Notebook sales overall continue to be really strong."

Baker said he thinks Apple Store's positive retail experience is a stronger driver of Mac adoption. Apple garners 18 per cent of all US retail PC sales, according to NPD Group's analysis of the first five months of 2008, up from 14 per cent in the first quarter.

And Mac sales overall are strong. Its market share has been growing steadily for several years, and now stands at more than seven per cent of all US PC shipments, according to IDC's first-quarter 2008 calculations, up from six per cent at the end of 2007. That is a growth rate of 51 per cent year over year. The industry-average growth rate for that same period was five per cent, said IDC analyst Richard Shim.