The highest quality experience.
For me will be between VIVE and Oculis Rift.
Project Morpheus has no chance, since is console. (so less powerfull system, higher system lifecycle, lower quality experience, restricted market and service).
I really dont believe Razer is big enough to distinguish itself from the big hitters.
Vive will have the quality and Valve backing.
Oculis Rift will have the price leveraged by the huge financial of Facebook.
But regardless, I believe game support on pc/linux games will all support all (except morpheus which is doomed unless sony make drivers for PC/linux).
Only the quality/price will be a factor.
Even on Steam machines, I think I will be able to plug my Oculus Rift for example.
And unlike consoles where price is a huge factor. First adopters will be the tech savy that want the best experience, even if means paying more.
And of course availability will count. The company that has the backend to distribute to most countries and people may get ahead, cause interest may rise quicker than manufacturing can produce, and people my gravitate to competition if that happens.