Here are your correspondent's initial impressions.
Overall, there didn't seem a huge difference in the quality of the experience with the two HMDs. The Vive's industrial design seemed a bit more polished, and it's possible that one of the reasons why a particular HMD was chosen for each demo was the suitability of the hand controllers for the application. It's easy to imagine a variety of controllers designed for different purposes (eg, a glove, a wand or a pistol) but it's questionable whether they would be affordable. But we do know some gamers are willing to spend up on peripherals.
Time did not permit an investigation of how well or easily the headsets can be adjusted to accommodate imperfect vision - neither were comfortable over spectacles.
Bullet Train (Epic Games) - A SF shoot-em-up set on a railway. The idea of catching the opponents' bullets and missiles and throwing them back was an interesting twist that adds to the physicality of the game. One problem was fighting a strong urge to walk around the scene rather than using the character's teleport capability - it's all too easy to collide with a wall or other real-world object when wearing a headset.
EVE: Valkyrie (CCP Games) - The traditional 'space shooter' gets a whole new twist in the VR environment. The feeling of sitting in a cockpit is compelling. For some reason, manoeuvring the craft gave the sensation that the field of view is rotating - that seemed no less real, but there's no nausea-inducing mismatch between eyes and inner ears. The game probably needs a really, really easy mode for beginners, as the targets seem to move much faster than the player's craft can be steered.
Trials on Tatooine (ILMxLAB) - Even in a VR environment, having the Millennium Falcon land almost on top of you is enough to make you flinch. Press a couple of buttons to reset an actuator, and R2D2 delivers a light sabre that you use to deflect blaster fire from attacking stormtroopers.
Everest VR (Solfar Studios) - A vertigo-inducing simulation of being at the top of the world's highest mountain. Having enough real-world room to move is important, and you need a 'spotter' to avoid collisions. The use of glove-style hand controllers to grasp ropes worked well, but walking along a narrow ledge when you can't see your feet is challenging (but that's probably a testament to the effectiveness of the simulation). A potential problem with this type of software is that it has limited replayability, so people might not be prepared to pay enough to justify what is presumably a fairly serious production investment.
Tilt Brush (Google) - Do you remember the excitement you felt when you first experienced MacPaint or its equivalent on another system? Tilt Brush brings that back. It's probably useless for practical purposes, but there's something very compelling about being able to paint in 3D in mid-air. Handheld controllers work for this application, and they appear to float in the appropriate positions in the virtual space.
All three games generate well rendered though not photorealistic environments (they look better in these scaled-down screen shots than they did on the HMDs), but that's not really an issue as you quickly become absorbed to a greater extent than traditional games. If you've fallen out of love with games in general in recent years, VR may be the innovation that rekindles the romance.
Whether or not 'serious' consumer VR is more than a gimmick remains to be seen. There was a lot of excitement about the previous generation of on-screen VR, but it didn't amount to much. People were content with predefined views of products in online stores and artefacts in virtual museums - the ability to rotate them to a particular angle wasn't a big deal. And Second Life attracted a lot of interest but in the long term its significance has been minimal - How's your 'investment' in Second Life real estate faring?
It's possible that the greater immersivity of the new generation of environments will make the difference, and some companies appear to be placing significant bets. But we're still not talking about a Star Trek holodeck - although 360-degree treadmills such as the Virtuix Omni help move the technology in that direction.
Disclosure: the writer attended the GPU Technology Conference as a guest of Nvidia