I haven’t run into any showstopping bugs. I’ve loaded a few apps, connected an Xbox controller and played a game I downloaded from Steam. And, hey, Netflix works.
As Microsoft has said previously, this is a “build” of Windows 10. Microsoft still has nine months or so until the final release. Hopefully this gives you a sense of what works in Windows 10, and how to make it better. What’s next is up to you—explore Windows 10, discover how it works, and if you find some aspect you dislike, let Microsoft know. There’s still time to make Windows 10 what you want.