FX-8350'tard here. 

So I downloaded and played Virtual Battlegrounds. 
In its native SteamVR mode it was unplayable, I couldn't even get a decent framerate in the little shooting-range/lobby area the game has, which is very small. I went into an actual match and it was as expected, totally unplayable and headache inducing. 

However, I didn't cry too much, I popped on the discussion boards and what do I see pinned at the top? "-vrmode oculus" as a launch option. 

So I restart the game in oculus mode and the improvement was immediate, framerate in the lobby was fine didn't hitch at all. Went into a game however and the framerate, while not nearly as bad as before, was not great, I had to turn render quality to 0.9x and LOD to 50 in order to play reasonably and then it was still hiccuping every now and then. This is a very early version though so perhaps some optimisation will come in the future? 

From the lobbies it looked like there was around 100 people online, I don't know how that ranks in terms of other similar style VR games.