As of this writing, Windows 10 should be released in about 15 weeks. The currently available preview build has (to my sense anyway) a rather alarming number of broken pieces. While it could be that Microsoft is actually a bit further ahead than it appears, and of course this is a TECHNICAL PREVIEW, I am still beginning to wonder if they will realistically have a quality product to give us at the planned release date in late July 2015.
When Apple release the first version of OS X way back in 2001, it was a bit of a steaming pile; but it was also radically different, and the Apple fans dealt with it until more functional versions became available. I don't think Microsoft has that kind of cachet with the computer-buying public anymore.
RegisterThis latest release does fix a few problems found in earlier builds. Indexing email in Outlook works again, as does enabling Hyper-V. Some UI issues have been fixed in the Project Spartan browser. And Visual Studio won't crash anymore when creating new Universal app projects – which, as much good news as it is for developers, is even better news for Microsoft, which desperately needs people to start building these things if the idea is going to take off.