As a VR dev/enthusiast, I agree that the Gear VR is surprisingly not bad (I have an S6 Gear VR IE) - the fact that it's mobile makes it really easy to share, and it's a huge leap over the cardboard (most people can wear it without getting sick). The resolution is better than the DK2 and the experience it provides can be immersive and fun - IMO, it's especially well suited for 360 video content (being untethered, 360 video doesn't support positional tracking anyway), but IMO, the Vive/CB/CV1s are on a different level.
Two things to note:
* Pixel density and screen door effect (pixel fill) are artifacts that are much worse in the Gear VR (and similar) than in most displays. The consumer PC-class gear mostly solve the latter, but some people are more sensitive to this than others. While using the Gear VR in a plane mostly beats any other way you can watch media, I wouldn't get rid of your 4K TV yet...
* Within VR, "presence" is actually a term of art that refers to a type of immersion which refers to the illusion/perception of being physically present within a virtual world. When this kicks in, it happens at a subconscious level, but its easily broken right now. One of the biggest requirements is solid tracking - because the Gear VR doesn't have positional tracking (handling translation), presence is rarely, if ever achieved. (Even when you're watching TV, pay attention to how often you move your head, even slightly and imagine if the TV moved along with your head movements).
If you'd like to read more about presence (like with most things I suppose) Wikipedia isn't a bad place to start: https://en.wikipedia.org/wiki/Immersion_(virtual_reality)
A pretty interesting paper I ran across while searching just now: http://www.ism.univmed.fr/mestre/projects/virtual%20reality/...