That is why I ask to load my setting if you are using Vive . It's very playable with good image quality on 1080 ( 90 fps ) and don't say it's pointless. SS should be lower and HMD quality maxed + reprojection "always on" at Steam VR. Works fine with beta 2.2
I've tried those settings and the game runs 45fps +, excluding in Haz Rez.... BUT - BIG BUT....
No offence intended, but playing the game with SS lower than 1 makes little sense. I keep seeing this offered as a solution and it makes me pull my hair out. Why should the dev even bother with Textures. Might just as well have some low quality plains of color on, as more we decrease the original sampling/resolution more we lose in Texture quality. Yeah sure it makes it "playable" (not in my eyes as there is more to game then just running) but it also looks like a game with terrible textures and if people don't mind that I give up. It is the same problem with Over supersampling. Overall the experience suffers. Also if Shadows, bloom, FX and Ambient lighting are off you really end up playing a game from 90s with good 3d assets. What is the point? VR should be immersive and not a simply a throw back down the memory lane.
Atmosphere of the game is butchered with 0 shadows or fog or anything else that would add atmosphere. The problem with Vive is that you can't get a desirable quality - Shadows- Medium, FX - Medium, Bloom - Medium ect without undersampling ( if you want the clarity to improve with supersampling) thus loosing great deal of visual quality.
The point is that supersampling so high while undesampling at the core output is just terrible idea all around... Try running the game in Beta (if you have it or later once the 2.2 goes live) and run SS 1.25 and HMD quality 1.25 (effectively renderTargetMultiplier setting in ED, so no need to edit the steamvr file anymore) and then tell me how it looks. The Resulting conversion will be the same, but the visual quality of Textures and general surroundings will be considerably higher (check the cocpit or ground ect..) The difference is that on Vive you still need to switch AA, Shadows, Ambience, and the other usual suspects off, but with Oculus you get away with having them on Low or medium (excluding ambience) and you get to play the game with very small amount of issues - probably almost none on 1080 (I'm running GTX 980ti, so I'm considerably underpowered compared to your rig

)
PS In my opinion the text is readable at SS 1 and HMD at 1.25, but the AA issues are still terrible, so all I would wish for from FD is modern AA that would work in VR and Scale slider. I understand that AA might be some way off as it is not the simplest of matters when it comes to VR, but Scale slider shouldn't be so hard..