I played a crappy RPG (Summoner) right to its ending only because it looked perfect with a pair of shutter glasses. Without them it was completely forgettable.
I still have the glasses, but they're only (unofficially) supported on NVidia hardware, which is kind of lame. I'm an AMD/ATI user these days.
Still, real 3D really makes things stand out and feel larger. Consumer 3D in the shape of special screens and projectors is coming together finally. Shutter glasses are probably taking the Dodo road.
I've played full VR (headset, gun, etc) and found it fun but very tiring on both eyes and arm. You think holding a wiimote up to the screen is tiring, try putting a huge headset on your head and a gun with a big cable hanging from it on your hand.
Visuals were blurry away from the center so you had to keep your eyes pointing forward and look around waving your head, which was weird but not that bad. I'd go for it in a sitting/laying position and with proper head rest if it had a larger FOV so I could at least move my eyes a little around the center, as it is natural to do so.
I've also tried haptics and they're really good, but also really small and expensive and hard to develop for. Size really limits what you can do with it, so don't even think about wii-style big motions. Wrist only.