I'll open by saying I am not an authority on VR tech nor do I follow the scene as a hobby. I own an HTC Vive and have used a Rift once or twice.
TL;DR: I love my Vive, I'd spend the money above the Rift to get it, but that's not the right choice for everyone. Promising tech is on the horizon. Promising options on both the lower and higher budget ends outside of the Rift and Vive.
Oculus Rift:
Pro:
- Cheapest by a mile (unless you also consider the newer WMR devices)
- Same resolution as Vive (1080 x 1200 per eye)
- Lighter, more ergonomic controllers
- Many say it is more comfortable than the Vive, I'd say it is about the same. Head shape will be the main factor here so try both if you can.
- Perfectly acceptable tracking
- Out-of-the-box integrated headphones
- More space for googly eyes on the front without disturbing tracking
Con:
- Not set up for room-scale tracking out of the box (1-2 addtl tracker(s) needed @ $60 each depending on shape of your game area)
- Smaller theoretical supported roomscale area size
- Lower FOV than Vive (100 vs 110)
- Closed game ecosystem; there are very easy workarounds but it is an extra step
- Imperceptibly lower PPI than Vive
- Smaller accessory market (but they are there!)
- (Obviously subjective) Owned by Facebook
- No front camera
- Uses a ton of USB ports (one for headset, one for each tracking cam)
- Shorter cable than Vive (4m vs 5m (+1 from link box))
HTC Vive:
Pro:
- Same Resolution as Rift (1080 x 1200 per eye)
- Imperceptibly higher PPI
- Higher FOV than Rift (110 vs 100)
- Front camera
- Fewer ports on PC needed (just HDMI/DP and one USB)
- Open game ecosystem (can play Rift games with one addtl step [ReVive])
- Longer cable than Rift (5m (+1 from link box) vs 4m)
- Best tracking in the industry using Lighthouses which only need to be supplied power, not connected to PC in any way
- Richer accessory market (forehead fans, upgraded face pads like leather and velour, Deluxe Audio Strap, Vive Trackers to add more objects in VR, etc)
- Larger supported room-scale area (v1 Lighthouses can do 20' x 20' without significant loss in tracking. v2 purported to be capable of 30' x 30')
Con:
- Twice the price of Rift (gap narrows as Rift is set up for room-scale)
- Heavier headset and controllers (I personally like the bulkier controllers, they add a sense of presence for whatever you are holding in game)
- $100 Deluxe Audio Strap to get comparable integrated headphones as those that come with Rift (could be seen as a positive if you have nice headphones you wanted to use anyway, there is a 3.5mm jack right on the headset you can hook into)
- (Subjective) Less comfortable than Rift although both have a wide range of face pads to suit your needs.
- Must be careful where googly eyes are placed to avoid disturbing tracking
Additional Vive Info:
HTC recently announced their Vive Pro which introduces a number of feature additions and upgrades:
- OOTB integrated headphones
- More ergonomic head mounting solution
- 78% higher resolution (about 32% increased PPI)
- Gen 2 wands
- Gen 2 lighthouses
- Dual front cameras (dont worry, plenty of room for googly eyes)
HMD-only (upgrade your current Vive kit, rumors of a trade-in program) scheduled for Q1 2018 (next 2 months or so) and the full kit scheduled for a Q3 release. Prices not yet confirmed.
PIMAX:
I'll be honest on this one, I haven't looked terribly hard into it. I try not to get too invested in a product until I see a consumer-ready version and with Pimax they are 100% not ready for consumers. I've heard the bump in resolution (which is certainly not 8k, it is 4k for each eye which is half as many pixels as 8k) is something to behold.
I've seen a few Pimax videos and right now it sounds like the consensus is that the 200 FOV is incredible, the resolution is incredible, but the tracking is still far behind its contemporaries, and price is yet to be confirmed. Hopefully someone who follows this story closer can correct me here.
I personally won't bother considering the Pimax until it has been in consumer rotation for a little while, but do some research as the tech is pretty impressive. And you can look like a bug person.
Windows Mixed Reality (WMR):
Another category I don't have much experience with but from what I have read this market segment is very promising. Compared to the Rift and Vive, most of these headsets are very affordable and boast a higher resolution and PPI. I'm not sure how broad the game support is but I know people have played some popular Vive games without much issue at all.
One of the biggest pros for the WMR headsets is their "plug-in-and-go" style of inside-out tracking. This means that there are no external tracking devices that must be arranged in/around your play area. The limitations of this are that if your controllers are out of view of the tracking cameras on the headset they can still be tracked but only using the accelerometer, i.e. they must keep moving to be tracked. I've heard this causes problems in games that use "utility belt" style inventory systems where you otherwise would be able to interact with certain game features more naturally.