I don't need to repeat everything that has already been said here, but just buy this thing. It is the best purchase I have made in a very long time. VERY polished VR experience from both a hardware and software perspective. Absolutely zero lag anywhere. The inside-out tracking works flawlessly. I don't know what else to say, it is fantastic and way more fun than I ever thought it would be - do yourself a favor and pick one up.
One thing I will mention is that the smartphone based VR systems (Google Daydream, etc.) give me headaches and make me nauseous very quickly. This is not the case with the Oculus - I have played for hours on end with zero issues. I have no problems with it whatsoever.