I have installed the Enterprise technical preview on my main work machine last week to check the differences to our Windows 8 based corporate installation. And I have to say I am completely blown away!
By the name that is.
Because let's face it, after working on this for a few days - it is exactly Windows 8. If I wouldn't have reconfigured it to use the Startmenu (which I don't really want - I was fine with the Tiles) you would not be able to see anything different to Windows 8.
So the name that distances this from Windows 8 by two version numbers (and puts it on par with OS X) is the only real genius thing about Windows 10. Technology wise this is a service pack at best.