VIREIO, while neat (I use it for some games) currently has a LOT of limitations. Currently it only works with DirectX 9 (though they are working on that). At the moment I’d still take VorpX as they seem to be the better product, but if VIREIO does complete the enhancements they are working on it’d be a tie, which comes down to price…
Your current audience is taping Hydras to their foreheads for positional tracking and spends hours tweaking ini files to get things to play even in mono mode. You don’t need much polish to impress us :)
FacetrackNoIR current works for head tracking with the rift. You can play FSX right now using that plus one of the other rift drivers. Works quite well! Not perfect, but for sure will keep you busy until Vorpx, which will be any day now, right? :)