I am thinking of pre ordering the Vive anytime soon. How much better is ED with VR? Is VR a game changer? Please convince me!
To answer your question,here's what changes:
First, stop thinking that you will look at a screen when you put on the headset as you will not see a screen. You will be sitting in the ship, with everything around you to scale. It is also the hardest part of a user that has never used an HDM to grasp. Another way of thinking of it, if you ever used binoculars, think same but with a much wider field of view, or think swimming goggles. There is no screen to look at, there is only what you see, just like in real life.
That in and of itself is the game changer.
Having said the above, instead of looking at a hint of scale and grandness on a screen (monitor), your reality is actually transposed into the game with all it entice: Vertigo, scale, speed (or lack of) visibility - you can look for what you want to see instead of limiting yourself to controllers (or buttons) movements.
The drawback (with the DK2 but to some extend also the newer devices) is that you do lose some of the resolution that you get into a monitor, so while grand the picture is not perfect, but most people soon forget this as the rest of the experience is overpowering.
As for which HMD, well it all depends on what you want to do. If only Elite, then either will do. If you want to experience stand up and move games, initially it will be the Vive as the controllers are superior to an Xbox gamepad. The Vive also probably has a better way of defining and tracking larger volumes. Once the Oculus touch is out then that may change. In any case, neither devices have faced the perils of mass production and uses yet so there also may be issues with the products quality themselves in the future that no one has found yet.
Since you have not yet ordered a Vive or an Oculus, I'd suggest you wait as by now it will probably be June before you can get one and the backorder will only diminish as we move forward and the companies ramp up production.
So, VR = Great, HMD = verdict still out.