I've spent a bit of time with both the Vive and the Playstation VR now and while the Vive seems to have slightly higher quality screens, the Playstation VR is quite a fair bit more comfortable to wear for extended periods of time for me and would be my purchase preference were I to buy one.
Which I'm not just yet.
So far of all the things I've played and experienced, only Rez Infinite in VR is worth it. It tracks the target reticule to your head and you may think this would have you tracking wildly but you don't at all, it actually makes Rez a bazillion (scientifically measured) times easier than using the analogue stick, and the game a kajillion (also scientifically measured) times more enjoyable than it was before, which seems impossible but it is. The game is astonishing in VR and an absolute blast.
On rails experiences seem to be the best, but as for user-controlled movement, in comes the nausea.
I don't know if it takes getting used-to, but both the owners of the units, everyone they've given demonstrations to and myself, have all experienced varying degrees of nausea in games where we control our own movement with a stick and not our bodies moving within a limited three dimensional space - ie, FPS controls. Standing up, moving the character forwards makes me feel like I'm falling slightly backwards, and if I instinctively pull back on the stick, the nausea leaps ten-fold. For me, if the walls are closed-in such as in a hallway, the nausea increases whereas one of the owners experiences it more in open areas. They actually experienced much more nausea than I, as I endured quite a bit farther in a particular game than they did, but I still couldn't stand it after a while.
So at the moment, I can't justify buying one just for Rez. I'd love to try it with Bound and see if it's as nausea inducing if the implementation is more of a chase-cam rather than a first-person perspective, but even then, two titles still doesn't warrant the cost.
The last concern I have is one of dept of field which I discussed on twitter and won't repeat here - long story short, for the most part, I still don't think the illusion of depth is created effectively enough, consistently enough, and for the money, that's a problem.