Stretching the definition of a PC here but it is interesting they have ported SteamOS to ARM with x86 translation.
The remaining 10% still remained with the HP Reverb and the Pico 4 which I've used quite a bit, so it's not a solved issue but it's a world of difference from the old Vive or Quest 1 if that's your reference frame.
("pancake lenses" is a similar upgrade over the old fresnel lenses)
It's a lottery rather than first come first served. Valve randomizes everyone who signs up before Thursday at 10AM PT, so there's no advantage to reserving in the first five minutes, and late signups just go to the back of the waitlist. Half-Life: Alyx has a native ARM64 build that runs standalone on the headset with no PC involved. Valve says eye-tracked foveated rendering was what finally made it feasible, on top of roughly a year of Vulkan driver and SteamVR work. Some of those Alyx optimizations apparently carry back to the Windows build too. Since I already own Alyx I'm curious as to whether I can gift the second copy to a friend.
I'm curious how well Proton and FEX actually hold up for the flatscreen catalog running on-device. That seems like the more interesting question than the VR-native stuff.