I have the Rift DK2, and I have to say, it's a game-changer. The higher resolution means that all of your dials and such are readable, there is almost no image latency now, and I may be a freak, but I can wear one for hours without any ill effects.
Scawen has done an amazing job of getting everything to work seamlessly in VR - it's quite simply the best game conversion available so far. No fiddling with settings and screen configs, no having to use a screen for menus and then back to the rift to race... You set it up once, and it works every time after that. Simply brilliant!
The only problem with it is that while you are completely immersed in the game, you are unable to see your keyboard or other peripherals, which makes it a little hard to communicate with others. I'm slowly finding ways of working around this...
After I had been using it for a few weeks, I decided to play on a screen so that I could be a little more social. I had no idea how difficult it would be - I almost had to re-learn how to drive! I don't think I'll ever go back to playing LFS on a normal screen if I can help it.