I'm a few hours in...this game is absolutely amazing! To see striders and headcrabs to scale jumping at you, the environment, lighting, everything is top-notch. HL:Alyx alone is worth the $400+ to buy a VR headset.
Edit: You get so immersed in the game that you forget you're in VR sometimes. I've tried physically leaning on railings that aren't really there. Once I was laying on the floor crawling under a virtual desk just to see what it was like. Somehow I lined it up perfectly so when I hit my head on the leg of the virtual desk I hit the leg of my actual desk at the same time. Scared the crap out of me.