For what it’s worth, the first official reviews are coming in, and the major tech website CNET titled its review, “Microsoft gets it right.” For a brief summary, they have three bullet points at the beginning --
THE GOOD Windows 10 bridges the gap between PCs and tablets without alienating anyone. The new OS combines the best bits of old and new Windows features into a cohesive package, while correcting nearly all of the missteps of Windows 8. The upgrade process is mostly painless, and free for most Windows 7 and 8 users.
THE BAD Many of the new features will be lost on those who don't care about touch. Automatic, forced updates could spell trouble later on. Cortana's features are better suited for smartphones.
THE BOTTOM LINE Windows 10 delivers a refined, vastly improved vision for the future of computing with an operating system that's equally at home on tablets and traditional PCs -- and it's a free upgrade for most users.
You can read the whole review here. But even here, as far as the "bad" points go, they're pretty minor. Mainly, "not everyone will need all these features." And "maybe there could be problems later." (Keep in mind for this latter point, most Windows users have had Auto Updates set as their default for years, with no problem.)
As readers of these pages now, I've been writing for a long while that, from what I've seen and read about Windows 10, it looks to be a seriously significant operating system. I liked Windows 8.1 a lot (it's version 8.0 that caused more confusion for users), but Windows 10 appears to take the best from Window 8.1 and the familiar from Windows 7 and added some fascinating new tweaks. (One, for instance, is that a tablet or monitor automatically knows if a keyboard is attached or not, and the system will adjust the tablet screen or monitor accordingly for touch-specific features or keyboard/mouse features. No user intervention is required.)
This video below is a 4-1/2 minute, very low-key introduction to a general overview of Windows 10. It's cursory, but still does a respectable job covering the basics and in a fairly-understandable way.
Two minor things that might not be perfectly clear, that are taken for granted in the video. "Cortana" is the Windows version of Siri or Google Now, a voice-activated "personal assistant" that has been a feature of Windows Phones but is now added to Windows 10 for all Windows devices. And "Snap" is simply a feature that docks a window to the edge of the screen.