Price and as others have said whichever one gets support from the porn industry.

I donnt think iit's going to be as much of a hit as many seem think it will be. It's not going to be a war...

Platform+content

Sony has it in a bag, no contest. It has a unified highly successful platform not only for people to develop on and sell their games through but also for the VR to be sold and marketed alongside. I don't see many devs making meaningful content for Oculus but then ignoring Morphues, whereas Morpheus will most definitely have big exclusive experiences. I also don't see many people spending $200 on something they connect to their PC. The simplicity of console package is will also apply to the morpheus but then I guess that brings up a better point actually, Sony and the others won't be in direct competition the same way PC vs consoles aren't really direct competition.

Sony will be the mainstream option for the average geek/gamer, fringe consumer who wants to try out VR and the others will offer more of a niche experience. I don't think VR will be crazy big this gen but I see Morpheus doing similar numbers to kinect but over a longer span of time. Kinect lasted like 2 years, VR on PS4 will be here til the end of its life (I hope/think).

Honestly, it's the price and games. Whoever has that down, they win. But it can also backfire. If the market doesn't want VR. Just like how 3D failed, after a while. You only got so many people that liked the idea. The rest where like this is pointless.

Whoever has the best VR tech out the fastest at a mainstream price.

The first to get out of the VR business is the big winner here, ask Nintendo (kidding, of course).

Nope. When they can project holographically, or make a headset in a less cumbersome scale (glasses), I'll be in the fringe market. Right now, I have little to no interest. Then again, they need these stepping stones to make better hardware in the future - I'm just not interested enough to pave the way for a device I MIGHT want eventually with dollars spent on something I definitely don't want now. 

it will not be a "big hit" by next year when most of the 1st gen of high quality VR sets are released, but it very well might be an established way to consume games/videos/... (along with normal TV/monitor screen based gaming) within the next decade

1. First party games and Third party games.

2. Hype.

3. Established platform.

Yep, but this is pretty much how most of the tech sector works. Someone may come up with a 3rd or 4th gen VR headset alongside a "killer app" and that'll be when it takes off.

Possibe? Sure. Probable? Hard to say. There is still the head. Ggear which many aren't going to want to wear, at least for now, and there are still issues for people that have eyesight problems. Beyond that there are still loads of people that get headaches, nausia, dizzyness among other things from 3D movies. Plus the weight on the head even though it is a small amount can cause neck and back strains for some people. 

There will certainly be a portion of the population that doesn't have any of this, but it could very well stop it from being mainstream.