The cost probably won't put one over another at this point. Mainstream demand just isn't there, and likely won't be for some time.
(Long post ahead)
I strongly disagree. I think the uncertainty of the technology means the pricing of the headset will be the deciding factor behind mainstream adoption.
It's very important to remember that demand can be heavily influenced by early adopters. This is why it's extremely important to 'get it right' at launch. If word of mouth is extremely positive, then you will see demand shoot up. People will Google stuff and go shopping for a VR headset, and it is at that point where the cheaper device wins. The cheapest VR device simply has to be 'good enough' and have access to popular VR content in order to earn a purchase.
The mainstream/casual consumer will simply not care about refresh rates and whether or not the headset has a high-end OLED screen. Price, accessibility, content, popularity, comfortability, looks -- this is, whether we like it or not, the criteria that the average consumer will set in place for purchasing one of these headsets.
Based on what Oculus has announced, what Sony are doing, and what the Vive seems to be doing, I will say that there are two big mistakes that each company is making that will affect mainstream adoption and perception:
Oculus
Mistake #1 = Not having Oculus Machines. Let's face it -- having pre-built machines that are 100% compatible with the Rift would save a lot of time and headaches for the average consumer. When a major part of the Oculus conversation is whether or not you can actually use the device, then I can guarantee you that the average consumer will gravitate towards the VR solution that is 100% usable. I understand the complexities behind pre-building machines (the shipping alone can be nightmarish), but with Facebook behind the product, you would assume the extra muscle would eliminate a lot of those difficulties.
Mistake #2 = The Xbox One controller. The Xbox One controller is the
Xbox One controller. From a promotion and marketing standpoint, when you see an X logo on a controller, you instantly assume the controller is meant to be used on an Xbox console. This wouldn't be a problem if the Oculus Rift was built for the One. It's a problem because it's a device built for the PC. The average consumer is going to see the Xbox One controller in Oculus promo materials and think "This is an Xbox thing". This association is valuable to Microsoft, but it's a world of customer support phone calls for Oculus.
PSVR
Mistake #1 = The Move controller. The Move was a controller for the PS3. It's very handy (pun unintended) that the controller can be 'forward compatible', however, casual and mainstream consumers do not want to be associated with been-there-done-that experiences. The Move is a been-there-done-that device. The Dualshock 4 isn't -- it is a new controller. Sony has not effectively communicated that the Dualshock 4 is compatible with the PSVR. The average consumer does not care about the increased fidelity of the Move controller, so with that in mind, Sony needs to communicate that the PSVR games are playable on the DS4. It's imperative that this new and fresh experience isn't tied to old and done experiences.
Mistake #2 = Playing it safe. If the PSVR is meant to be both a device for gaming and experiences, then Sony needs to stop ignoring the experiences part. There was a developer on a Giantbomb video who joked about making a Vomit Simulator for VR. Now, I'm not saying that Sony should make a Vomit Simulator. What I'm saying is I can guarantee you that an out of the box idea for PSVR will generate astronomically more interest in the mainstream than Tekken #7 having VR support. If they want this thing to fly off shelves then they need to invest in the things that will make your mother and 4th grade English teacher want to experience. Cutting My Hair: The Game, Holy F*** I'm Flying to Space Simulator, Hunting with Grandma, Zanzibar Simulator, Become the President, One on One with Serena, Get Out of a Boring Meeting 2016, etc. This is the stuff that will -- again, whether we like it or not -- go far beyond the pages of Gamefaqs and land on the HuffingtonPost's, HollywoodLife's, and Bleacherreport's of the world. I cannot stress how important it is for (what is looking like the cheapest and most accessible headset) the PSVR to have experiences designed for more than just us. I remember it like it was yesterday when Nintendogs, Brain Age, and Wii Sports were mocked to death for their simplicity and non-hardcoreness. In hindsight, those titles quite literally made the mainstream associate every ounce of casual gaming with Nintendo, leading to record amounts of sales, interest, and support for Nintendo products.
Vive
Mistake #1 = Freedom of movement as a selling point. Mainstream consumers will absolutely bite at the 'coolness' of being able to walk around a virtual room, but they won't swallow when you tell them you have to rearrange your furniture to make it all work. This is the Kinect problem reborn with Steam's logo. The novelty of being able to physically move around wears off the second you realize there are severe limitations to the movement. Furthermore, when your eyes are completely obfuscated from the real world around you, the last thing you want to do is start walking around and possibly trip over Mimsy, the family dog. You can test this out for yourself. Hold your phone close enough to your face that you can only see your phone. Then, make an attempt to walk to your kitchen and back to where you're seated. If done correctly, you will immediately realize why a stationary VR experience will be significantly more appealing to a mainstream audience.
Mistake #2 = Branding the Vive as a premium device. This one is really straight-forward. There is nothing that the Vive has shown or revealed that warrants the premium tag. The headset isn't wireless, the resolution isn't leaps and bounds better than the competition, the controllers don't transform and have bright lights on them, the cameras aren't able to sing the national anthem, nothing. Guess which audience of consumers will invest time and energy into criticizing your product for not being what you claim it to be? Enthusiasts. Basically, Vive is targeting an audience of people who can smell BS from a mile away, and once they smell it, they will take note of the time and place they smelt it and warn others of the stench. Furthermore, the enthusiast market simply cares more about the Rift than the Vive because the Vive is perceived as a me-too device. There is a tremendous amount of goodwill that comes with being the 'first' one to do something, and it is the enthusiast market that generates and distributes a lot of that goodwill. In other words, HTC has an extraordinarily slim chance of being the #1 headset for enthusiasts...which leaves the mainstream market.The mainstream market prioritizes pricing over everything. If you have branded your product as the 'premium' device, and you have priced it as a premium device, then you will need a miracle and a half to attract the price-conscious market. In other words, HTC has an extraordinarily slim chance of being the #1 headset for casuals. In summary, the branding of their device cannot satisfy the needs of either audience. It would be tremendously short-sighted to write the Vive off, but the market is just not siding with the headset.
In closing (and in the spirit of the thread), I will say that I think Sony has the best chance of being the market leader in VR due to price, access, content, and popularity. I think the PSVR will start at $299.99 and have options that go into the $399.99 range. I think the Vive will launch at the same price as Oculus, but due to the lack of outstanding features and software, it will be the least-adopted VR headset out of the three. Furthermore, I think StarVR will compete with the Ouya in sales-figures and messageboard jokes, and the fact that there are hardcore gamers who didn't know this is an actual thing should tell you how much of a shot it has in the marketplace.