Both nVidia and AMD are slated to release new cards this year. First new node shrink in many years, so it will be a big jump in performance. AMD is expected to release in the June time frame, and nVidia in the fall. Do not buy cards now unless you have to.
As for which to get, it depends which VR headset you want. HTC has been working with nVidia, and Oculus has been working with AMD.
AMD's current cards are better at VR than nVidia, but that could easily change once the new generation cards come out. We simply do not know, and there wont be any VR games released for some time.
So I say sit back, and see what unfolds this year.