I owned a Rift for a couple of years, and was pretty impressed with it. The additional level of immersion when you're sat in the cockpit of an F-15, or on the bridge of your Anaconda in Elite Dangerous is impossible to describe, other than it's pretty damn cool!
For some reason I was fine with flying games, but struggled with motion sickness in racing games where you have the ground/floor as a frame of reference. No idea why, as I don't get travel sickness. I can't see how that could easily be solved, but if it could then I'd definitely look at VR again (although not an Index, with its absurd price).