The preview of Windows 10 is available for download now from http://preview.windows.com. The standard reminder applies–this is for testing. It’s a beta operating system, with all the “We will not be blamed if you lose it.” that implies. The real thing isn’t this, and the shipping date isn’t announced yet.
After only a quick install and some exploring, this looks like what a hybrid interface should have been. The interface-formerly-known-as-Metro, or ‘live tiles’, or the ‘modern desktop’, hasn’t shown up at all. Apps are available from the desktop, and sizable, and they don’t break if your local sign-in to the computer was a local account–you can sign into them with a Microsoft account individually.
So far, so good.