I just got a DK2 for cheap and tried it out on the Huey was the scariest thing I've done, I think it's the disconnect between flying and not flying that does it, I've piloted a real helicopter with no doors and no scares, also got a bit sea sick which I was surprised about because I've never had issues before.
Was extremely fun though, I'm pretty sure the Oculus will support everything the Vive does in the end, so I hope it will not matter too much which one you chose, I've preordered the Oculus at least.