Microsoft has seen in recent years as consumers have embraced tablets, particularly iPads, not only for personal use but also, to the surprise of many, for work, triggering the trend known as BYOD (bring your own device) to the office.

Microsoft's sense of urgency is such that it has even decided to release its own Microsoft-branded tablet, to improve the chances of success for Windows 8 in this market, although the move has rubbed some of its device manufacturing partners the wrong way.

A key question for Windows 8 is how much support it will get from application developers, a crucial element in the success or failure of a new OS. In its RTM announcement on Wednesday, Microsoft pointed out that come Aug. 15, developers will find in the Windows Development Center "all the tools and resources" needed to build Windows 8 applications, including the final build of Visual Studio 2012.

Gartner estimates that there will be around 150 million PCs sold to consumers pre-loaded with Windows 8 in this year's fourth quarter, which should be a big enough audience for Microsoft to attract a lot of app developers to the Windows Store, Silver said.

"But so far the store is not very user-friendly and doesn't have enough of the titles that have made iOS so successful. It better be much better by the Oct. 26 launch," he said via email.