I bought Google Cardboard VR and now GearVR. I have not tried the real Oculus Rift yet not Google Daydream
Pros:
These are miles and miles better than Cardboard VR. Very well thought out built product. Handheld remote is a quite welcome addition. It creates a visual "laser pointer" in VR and makes navigation much more intuitive.
Cons:
Mainly the resolution issue. My S8 display is
2960x1440 and GearVR makes a point of switching the phone to that resolution if not already set. Sounds a lot, right? Wrong. So each eye should get about 1480x1440, but due to optics loss which I can't properly explain, some idea here:
https://medium.com/visbit/why-do-all-the-360-vr-videos-today-look-so-pixelated-b1ab3cba6f95, you actually get something that looks like 640x480 or less
But essentially, even tough for regular smartphone usage current DPI is already very high, even unnecessarily so, but for VR is nowhere near high. It needs to be about 8k so each eye would get a mere 720p image displayed.
For now, it's still a pixels showcase. Usable for videos. Plex virtual display could be cinema sized huge, but the resolution is disappointing.