I got to play with an oculus rift dev kit yesterday. It's pretty neat as a proof of concept, but nothing more. It's 720p, but due to the way the lensing works, it felt like gameboy resolution. The pixels right in the center of the screen appear to be enormous, but the ones farther out seem to get smaller. It did fill a lot more of my vision than I expected, and the motion tracking was pretty decent and responsive (though there was a little bit of lag.) It only mapped rotation though, so that felt a bit odd. There was also a lot of chromatic abberation from the lenses. I lasted about five minutes before becoming severely nauseated and dizzy.
Overall, it's pretty cool though, and definitely has potential if they keep developing it. I would not suggest buying one unless they get the resolution to at least 2560x1440. Even then, it'll still be pretty pixelated looking, but I think that'd be the point where it doesn't completely break the experience anymore. Keep in mind that what I used was just the dev kit, not the finished product, so we'll see how it improves before the consumer launch.