While I have not had as much time to play with the Windows 10 Technical Previews as much as I would like, I do like what I have seen in Windows 10.
My test Virtual Machine is a bit out of date, but it's fast, responsive, and I've had absolutely no problems with it. The most important thing is that it is much more intuitive. With the hybrid windows start menu back, it's easy to find any application that's installed on the system so figuring out how to use it isn't a problem. Performance (very subjective) of the OS is as good or slightly better than what I'm seeing in Windows 7.
My biggest concern is (of course) if Atrex would run on it. So far, I've not found any issues with Atrex 15 running under Windows 10. That doesn't mean that something couldn't be introduced before the final release of Windows 10, but it's a good indication that there shouldn't be any problems going forward.
On a more geeky note, I do love that they named the "AI" assistant Cortana. I loved the older Halo games, so incorporating the name of the AI in those games into their flagship operating system was pretty cool.