It's a nice round, clean number. It's one they're likely to stick with for a while. And it's free, at least for many users. That's important, when you realize that Apple has had low-cost or free upgrades for a while, and how poorly received Windows 8/8.1 were with consumers. I myself never cared for 8, warmed to 8.1, but never found any need whatsoever for Microsoft's "new"-style apps. I know they were going for cross-platform uniformity, for ease of transition from phone to tablet to laptop to desktop. But these different devices have very different purposes, and the use of Windows on tablets and phones is very low. Windows' installed base on desktops and laptops is so large, and the users are so well versed in the platform (particularly in XP and 7 flavors), all their effort did was alienate people.
Windows 10 purports to revert back to familiar ground, and that will be welcome. What worries me, is that my "early adopter" urge always wins out over my better sense of caution. Undeterred by issues I had as a beta downloader of Windows 7 and 8, I jumped on Microsoft's offer of "release day" candidates for the 10 upgrade. Now I'm a little bit worried. In both of those cases, there was quite simply no going back. It couldn't be undone. But the chief problem then, was that they were limited time offers that forced me into pricey upgrades later. This time it's free. So, my big worry is that a) some hardware I use will no longer function properly due to driver issues, and that b) some software I used--a few of which weren't supposed to function properly with Windows 7, let alone 10--will finally be non-functional.
Add to that, that I use Parallels on my MacBook Pro to run Windows 7, and I'm bound to have a few Computer Woes posts here on the blog! But here it comes folks, ready or not.
Read more about Windows 10 here.