To start, when I bought one black friday 2015, I had planned to buy another one. But after a year, I still followed through with that plan.
VR Ready? Technically.
4K Resolution? Yup
4K Gaming? Really Depends.
Testing went through a couple phases. We have a few (4) custom built computers lying around. My wife has the 4k screen so we tossed it in hers first. Paired up with an i7-6700k and 16gb of ram. Running the editing software she uses on the two screens (1x4K, 1x1080p) seemed to have no problems. Cuttting down to just the 4k screen and running Wticher 3 max settings, things seemed to get a bit chunky and frame rates dipping into the teens. So it will get the 4k, but I don't think it will truly game at 4k on some of the more demanding games.
Currently it lives in my rig. Asus 990FX r2.0, 32GB RAM @1866MHz, Fx-9370 @4.4GHz
On the single card, 3DMark Fire Strike was receiving a score of 8720, Fire Strike Ultra got an overall 2735 ( For reference, Ultra lists Vive/Rift Minimum spec score of 2596. So technically the single card is enough to VR, but just barely. I mostly game on a BenQ 2K 144Hz monitor. I've been playing fallout 4, witcher 3, Skyrim, etc, maxing settings on 2K. With freesync enabled, I've held constant frames of 60Hz with no dip. Oculus rift was, as expected, toned way down, and till got some major frame rate drops if there was a lot of passive movement while looking around.
Tossing in the second card, with crossfire enabled, Fire Strike/Ultra overall scores were 11,080 and 4338 respectively. As expected, graphics score basically doubles, physics score increase was next to nothing (10 points), combined score saw about a 70% gain, allowing for that roughly 60% gain on the overall score. Running Oculus, decent settings with no frame/chunky issues. Tossing the two into my wife's computer and we gamed for about 30 minutes at 4k with 30-40FPS.
Some of my short comings on the scores are, of course, the DDR3 Ram and last gen AMD processor. Looking forward to seeing what gains I can get running with a Zen/Ryzen after they launch.
All in all, a great GPU. Now that the 400s are out, great bang for you buck on the price. and the 8GB card can take just about anything you throw at it on it's own, two of them chews everything up.