The OG Vive is great. A bit of a screen door effect from the lower pixel density, but mostly unnoticeable in most scenarios. It hurts the most in things like Elite: Dangerous when you're trying to pick up all the small details in your cockpit like the HUD and such. I do wish it had a slightly larger field of view.
I might sell my Vive kit to my parents and upgrade to the Index since I got my mom hooked on Beat Saber and a few other games. Between Beat Saber and Boxing VR you can get a pretty great workout in a short time, and they just generally enjoy some of the other experiences that transport you somewhere else like The Blu.
As for a good launching point for VR, and as much as I hate anything related to Facebook (especially their recent terrible decision to require a Facebook login for anything Oculus), I think the Quest and "rumored" upcoming Quest 2 are likely the best way to get people involved. Stand-alone (no PC required), light, inexpensive, and capable for someone to just pop on and have a great experience out of the box. No setup with camera or tracking boxes, just a headset with hand / finger tracking and a built-in store. Can also plug it into a computer with a USB-C cable for the higher quality desktop experience.