Oculus Rift and Vive (by HTC) are VR systems powered by a computer. Cables running from the headset to the PC, and you need a pretty boss system to handle it. This isn't cheap stuff now. And, neither have actually launched. Oculus has had dev kits that were $300ish, I think, but the real deal consumer version launches in a couple months.
Oculus is just a headset. Vive requires a couple sensors in the corners of the room and is a bit more precise. It should cost more, but who knows. They want to compete.
The Samsung thing is sort of a scaled back cheap version. It works, and there's some software by the Oculus team, but it's not the same thing.
Google Cardboard - There's a few video apps that are cool. I took a bunch of 360 panoramic shots on vacation and those are cool to show people and see. I thought it was neat for $15 bucks or so, but that's it. I'm not watching youtube videos or netflix on the thing.
Friends have tried with the Samsung version for your phone. They typically complain of headches and nausea. The better versions have better screens that are tuned to ideal measurements.
One of the hardest parts with VR so far has been people getting sick and headaches. Taken years to fine tune and find out what refresh works, etc.
Hope that helps clear things up a bit.