Each has its pluses and minuses.
Rift S has the convenience of inside out tracking, good resolution, an RGB stripe display for minimal SDE, reasonable hardware requirements and is very easy to set up. The LCD screen means colors won't be as vibrant and black levels won't be as deep. The software based IPD means people outside the average range may not find it comfortable and the speakers built into the headset are OK at best. At $399 it's a relatively inexpensive entry into PC VR.
The Index has nice resolution and the potential for great refresh rates but you need a beast of a computer to get the most out of it and must deal with external sensors. The sound system is excellent and it has mechanical IPD adjustment so it should be comfortable for a wider audience. FOV can be very good but only if you push the lenses right up to your eyeballs, which people with glasses cannot do. The LCD panels mean it also has slightly compromised colors and by all accounts the black levels are the same or worse than the Rift S. The headset also apparently has pretty bad god rays / glare (comparable to first gen headsets) and gets quite hot on the forehead after about 40 minutes of use. And of course, the entire kit costs $1,000.
Vive Pro has a lot of the same advantages as the Index at about the same pricepoint including tracking stations though I've read it's not the most comfortable headset and appears to be aimed more at commercial uses than for the home market.
The HP Reverb has the highest resolution yet (two LCDs at 2160x2160 each) but suffers from relatively high mura and there have been complaints of reds smearing inside the headset. It's also a Windows MR headset and, quite frankly, Microsoft seems to have zero interest in supporting consumer level VR and their 2 camera system seems outdated compared to what Oculus is doing with inside-out tracking. The headset is also being pushed more as an enterprise device than a consumer product.
The original Rift CV1 is no longer being made and I suspect the original Vive will suffer the same fate once HTC releases its Cosmos headset. Both also suffer from lower resolutions, SDE, god rays and the need for external sensors.
In the end, I got a Rift S and have been using it for about a month. Personally, I think it's the best compromise of price, performance and ease of setup and use. The PC hardware requirements are also reasonable meaning you don't have to break the bank on a PC for it. I have it paired with an Alienware 17 R5 with 8th gen processor, 16GB of RAM and a Nvidia GTX1070 and it has handled everything I've thrown at it so far.
Last edited by TonyDP; 07-04-2019 at 06:40 PM.