I've got Oculus Rift myself so couldn't comment on Vive but I can say the DCS VR experience is incredible. An older Youtube video gives the Vive a great review and things can only have gotten better since then.
I bought the Huey and the Black Shark - the amount of detail and work that must have gone into them make it good value IMO.
Tempted by the Gazelle. At just over £25 it seems a good deal.
What would you recommend for HTC Vive VR?
I like Black Shark 2 because it's a single seat 'copter so you get to both pilot and shoot. It ruined all the fun when sims reached sufficient detail level to separate those two roles when simulating the Apache. :D