First, it is not cheap. You need a good computer to run it, and my 3770k with a GTX970 is barely considered sufficient. Then the headset... in Italy it is 599€ for the Oculus Rift and 849€ for the Vive, plus taxes and shipment.
The two headsets have similar resolution and characteristics, but while the Oculus ships with an XBox 360 controller, the Vive comes with two "motion tracking" controllers... which are really nice and work well - but at first they look quite strange. The other big difference is that the Vive supports full "room-scale" VR, which means that you can actually stand up and walk through your room - up to 5m x 5m.
The last big difference (maybe not that big for us simmers) is the software availability - while both can work with software distributed in other ways, the Oculus has its own store, while the Vive relies on Steam (which also has a VR mode). The Oculus at the moment has more games and in general a better support - and its content is (supposed to be) locked, so you cannot play it with the Vive...although of course you can find hacks on the internet for this.
The only word of warning on the Vive is that if you want to use it a room-scale, you need to have 2.0mx1.5m minimum free space, although some applications require 2.4x2.4 or more - I had to move some furnitures to make room for it - by the way there is a safety "chaperon" feature that will prevent you from hitting the walls by projecting virtual walls when you are getting too close to the real ones...very well implemented IMHO.
On the good side image is well filtered looks good... let's hope that P3Dv3.5 has a better implementation.
NOTE - FLYINSIDE P3D has some issues with Tacpack experimental features (HMD and TFLIR imaging)... the HMD will not work as intended, and TFLIR sometimes works and sometimes not. It may be better to turn those features off.
We simmers have an headstart with respect to the rest of the "gaming" population... we have been building virtual cockpit for years, and it is awesome to finally "feel" there. But Virtual Reality has a huge potential for games and education. The Lab (directly from Valve) is a collection of mini-games / experiences that will make you fully appreciate the potential of these devices. Some of the games are really funny... but the whole interaction with The Lab is amazing. Really cool - try it (it's free)!
STAR WARS: TRIAL ON TATOOINE
Yes, there is a official free minigame of Star Wars. Yes you can wield a lightsaber (cool!)...but the game is disappointingly short. Just few minutes and it's done - and not much of a challenge. It is free, but I unistalled it immediately.
Another free game, Quanero is a cool experiment in storytelling... basically you are a CSI guy in a futuristic bar in which a bomb exploded and a guy has been killed. You can rewind the time and look around and your scope is to find who has done what. Really cool and quite well done... it suffers a little from the fact that it is an indie games and so some 3D assets are not top-notch... but don't get me wrong, it is well done and a very interesting experiment.
I made a quick test just to see how difficult it would be to develop virtual reality experiences... and a look at the Unreal Engine VR support. It is quite good - and it would be possible to create something in a reasonable time...unfortunately, there is my real life job...
SO, SHOULD YOU BUY IT?
Well... it is a lot of money, and a pretty cool technology. Strictly speaking of flight simulation it offers an unparalleled level of immersion. For the first time in my life a computer program made me feel into the cockpit. It is great...unless you do a lot of IFR, then the resolution is a problem. Also, if you plan to use it with FSX/P3D you will have to face the poor frame rates - even with the magic of FlyInside you may feel a little uncomfortable.
The best things is to try before you buy. Don't get me wrong...it IS AMAZING. But it is also very expensive and my guess is that, in a couple of yearsm these devices will have better resolution and cost less.
In any case, Virtual Reality is probably the next big thing in home entertainment.