I'll admit: you got me, Microsoft. Free upgrade from Windows 7 and 8 and holograms, goddammit!
But seriously, it does seem like an awful lot of innovation for just a PC operating system. The problem I had with the briefing is that it was (as usual, it seems) all about how Windows 10 is going to "change the way we look at operating systems" as less about "here's what's actually new and will improve experiences from Windows 7 and 8". Holograms and real-time Skype are great, but not everything that makes Windows 7 and 8 great were mentioned. Gaming experience could be whittled down to holograms, office work and productivity programs could be whittled down to holograms, and pretty much anything else that sounded like true innovation for operating systems could be whittled down to... wait for it...
Bottom line: I'm excited, but I'm not at all in a rush to take the upgrade deal; I need to see more of what Windows 10 can do before I make the leap.