Basically, VR really IS stunning - but you can go back and head tracking helps with that
I tried some of that on Elite and DCS, the enjoyment just wasn't there for me anymore, but to each of its own

I use pancake mode when editing mission in DCS for example, but not always. For Elite if I was doing something more than pure rank grind for the vette, I used VR. Mining is especially zen in VR
Does vive + expense actually add anything above a cheaper but way more affordable oculus?
I would steer clear from HTC but that's personal preference, my Vive broke three weeks in and was in RMA for a month and required sending abroad to Romania (I'm in Poland). The experience wasn't a smooth one. Nobody knew what is going on with my headset and I basically got a refurbished unit three weeks in ☹
Also HTC tried so hard to be the apple of VR it's not even funny, and it hiked up the prices sky-high until they were forced to go to somewhat sensible levels by Oculus lowering theirs.
There's no "python of VR" currently on the market, all have pros and cons.
Vive, Vive Pro, Cosmos, Elite I would steer clear from for the reasons outlined above. Worth to mention that they use laser based tracking (at least the vive family, cosmos needs a special faceplate available separately for $$$ IIRC).
Oculus Rift S - do not recommend currently as Quest 2 is cheaper and in almost all aspects better, also facebook stopped producing them IIRC.
Valve Index - pricey, has decent image quality which was top of the crop before HP Reverb came in. Pros include:
- COMFORT - index is really comfortable for long sessions (for me)
- laser-based tracking - this can be a pro and a con depending on your room. Basically Index uses two satellite stations called the lighthouses which you place on the opposite ends of the room, preferably on the wall or ceiling which shine laser rays which the headset and controllers pick up and calculate their position based on that information. The tracking is flawless and has no lags, meaning if somebody was brave around to throw a 150€ controller to you, you would catch it as you would in real life. It's sub-milimeter accurate. The satellites require only power and communicate over bluetooth to startup and shutdown
- high refresh rate mode which you can use to have stable 60 fps with reprojection in more demanding titles like DCS. But for me high refresh rates in VR aren't a factor worth too much consideration. It's double funny because I can detect frame dips in my fps games from 120 to 110 level and I love high fps gaming. But in VR it's almost unnoticeable...
- Index also had the best in class VR audio which is simply brilliant (BMR off-ear speakers), much much better in producing spatial audio than any headphones and much more comfortable than headphones. But Reverb G2 has that as they cooperated with Valve and used the same design.
- Very good FOV (both vertically and horizontally) and has best in class image clarity - the area you can look around moving your eyes, in other words how much of the screen isn't blurry.
- Index also has best in class controllers (the knuckles), with finger sensing. The first thing my wife noticed when I put her in Half-Life Alyx for the first time was "OMG I HAVE REAL HANDS!". It seems like a minor thing but these are the details that multiply the immersion far more than you can imagine. Going back to vive "wand" controller when my knuckles were exchanged was frankly terrible
Which brings me to a con - their build quality is not aligned with their price to be honest. There are thumbstick issues. Better get those sorted before warranty runs out, because...
Cons:
- There's no repair service post warranty(!), at least for controllers. IDK about HMDs. Which basically means after warranty if it breaks you will need to buy another one. Not cool Valve, not cool. VR365 youtuber Anthony (I recommend his channel btw.) has found out the hard way.
- very noticeable glare and some godrays
- steamvr software is not as sophisticated as oculus'
- cable might break on you as it did on me, causing "sparkling" or "snowing" image, it looks sturdy but you'd better be careful with it.
HP Reverb (G1 or G2, the later being much better) - the resolution king. The Reverb resolution (2160x2160 per eye, this means effectively 4k per eye, or 8k per stereo) is unparalleled. Some describe it as monitor quality, and it's certainly better than the 1080p real monitor setups

In fact most of current VR is better than 1080p in my opinion. I don't have personal experience with the headset (damn pandemic), however the clarity area is said to be smaller than on Index. Audio is the same as the index. Controllers are absolute abominations, no capacitive sensing whatsoever (what is it, 2016?), and tracking is heavily dependent on your room having enough stuff / lighting / whatever magic they require to work and is a hit and miss according to the reviews. HP Reverb is best for seated sim games like Elite, anything requiring motion controllers and movement tracking you're better off with other headsets. I'm toying with the idea of buying one after they become available. And since I mentioned unfair HTC practices, it is only fair to mention how HP deceived their backers (people who preordered and are waiting since June or July) and sent the HMDs to shops and not to them. It is absolutely inexcusable. There are also dead headsets arriving, and people RMA-ing them are informed of month long waiting queues while the shops have the units on the next day delivery. WMR software is also a con, being an additional software layer between your steamvr and oculus based games. Hopefully the arrival of OpenXR will sort things out for future games.
The Pimax family of headsets is technically great on paper, but my personal experience with them was marred by horrible PiTool software and general jankiness and tinkering required to get them to work. They have the best in class FOV and some even use OLED screens (LCD seems to be industry standard as of now), though they're expensive. They also require lighthouse units like the Index and HTC hmds. Due to the fov, they are using canted screens, which at this scale requires special mode called "parallel projection" which saps the fps out of the games. Even the smallest fov setting on the pimax will be wider than the Index which is best from all listed so far. Skyrim VR on a wide-fov setting in the Pimax 5k+ was really something, though the thing where you appreciate this FOV the most is any driving sim. The more FOV you have, the more sense of speed you can convey.
And last but not least on this list is a device which is a standalone VR console (meaning it doesn't require a computer) - the Oculus Quest 2. It's my "silent favourite" in VR adoption. For Facebook hating people, you can stop reading at this point, because it requires you to use a real facebook account "in good standing" - so making a fake one can mean LOSING ACCESS to your purchased games! That's a huge con right off the bat. However what follows is a very nice, cheap (relatively) entry into VR for anyone. And the best part is, you can stream VR games to it from your PC! Meaning, all the "mature" headset titles like Elite Dangerous which you wouldn't even dream of running natively on the Quest can be played using it. Now this being streaming and either WiFi or USB-C link cable there will be some compression artifacts and whatnot, but you get pretty solid VR experience for a fraction of the cost, and a VR headset you can take on a trip with you. It doesn't require a computer, it doesn't require sensors, it's small and portable. And the basic version (64GB) costs 349€... This is a crowd favourite and it is climbing the SteamVR hardware survey like crazy. Facebook is also doing good work promoting VR to people, I think anyone of you watching TV from time to time has seen a Quest2 commercial at some point. And the resolution is only 25% less than the reverb, however keep in mind that the unit needs streaming from the pc, so it isn't a fair apples to apples comparison. The controllers being the progeny of the excellent Oculus Touch controllers are very good and feature capacitive sensors. The tracking is not as good as lighthouse and it can be spotty in some edge cases (aiming through a sniper scope in Onward for example), but overall it's great. Also Oculus' software is the best in class currently, nothing comes close.
If I had the money, I'd buy G2 for sims, Quest2 for on the go VR + wireless gaming, and Index for anything else. Sadly I don't have that much ;-) I'm frankly waiting for Gaben's answer to G2, but I'm not holding my breath. Current Index is on 8-weeks backorder, why should they release new unit when the current ones are flying off the shelves like crazy...