I'm an absolute obsessor over VR news, specs, reviews, speculations. I've played CV1 & owned Vive, Pimax, Odyssey+, Quest1, Index, Rift S, Quest2 (I'm not rich - I return or sell, and keep 2). I've had my eye on HP Reverb G2 big time - and let me tell you, that controllers-tracking issue ain't looking good. That's a real bummer to me, because (1) the resolution, (2) the full comfort/audio Index-style setup, (3) I am a believer in a future of inside-out tracking. IOT is (1) portable, (2) simpler setup, and (3) sells better (due to 2). Portable has been more important to me than I'd anticipated over the years (not during COVID obv.). So on IOT, that really leaves some cheap WMR options, which IMO can have some pretty hit-or-miss tracking based on environment (I've had very bad experience with WMR tracking, but I'm also spoiled by Steam Base Stations). As for Pimax, you'll really only like it if you come from a background hacking Gentoo Linux kernels with lots of time on hand. And Rift S is discontinued.

So in the end, it's down to two sane options: Index vs Quest 2. And luckily for buyers, that's a very distinct choice. Would you prefer a home-theater with surround-sound and huge sofas, auto-dimming lights, and a popcorn machine? But it'll cost you an arm & a leg + time in setup & maintenance. Or do you just want to watch movies on an iPad? It's cheap, portable, and once you're immersed in a movie, do you really notice the details anyway?

Those are the two I own now. Index is obviously God-like, nothing much to say there. Quest2 is less bad than I thought it'd be. And especially the IOT tracking, it truly is not a problem for 99% of scenarios (unlike WMR, which had me tied to certain games I could play effectively). You'll want Link cable if you don't have a modern enough router for Virtual Desktop streaming (I don't); and you'll definitely want an alternative headstrap (Elite Strap or the 3rd party Halo Strap). So after you accessorize $150, you have a very solid headset, plus it's portable. Of course, the Facebook thing so that's up to you.

I've got a tentative eye on DecaGear, but from my Pimax experience I'm not hopeful of no-namers with big promises. G2 was my deus ex machina, alas. Of course, some are fitting into their SteamVR pipeline, swapping out the Index HMD; but that's another story. So I think the decision goes like this:

1. Index. Home-theater style setup. No compromises, but expensive & time-consuming.
   1. Index Kit for the "just works" package
   2. You're willing to spend & tinker more for better resolution, Index Controllers + Base Stations, G2 HMD (and shelf the controllers). How to do this.
2. Quest 2. Portable, simple, & cheap.
   1. No gaming PC, just the Quest
   2. You have a gaming PC
      1. You have a modern, expensive router. Stream games via Virtual Desktop.
      2. You don't know, or my router is old-ish. Get Quest with Link (this link comes with a carrying-case too, and the whole package is cheaper than HMD + Link separately)
3. You want both: portable and powerful. (1) If you can afford both, get both; (2) if not, get Quest 2 & mod it. Search for Halo Strap vs Elitestrap, over-ear headphones, controller hand-straps, etc. I'd link things, but it's fast-changing.