All i have seen from them over the years is a bunch of unity demos and their headset which is a good implementation of the peppers ghost effect with some tracking. So yeah, nothing revolutionary and many people could probably DIY something that gets most of the way there, but great products can still be built by combining a bunch of existing technologies in the right way. I agree that their trade secrets are probably not really secrets though compared to stuff Oculus/Valve or MS are working on.