I bought one about six months ago and I will less than overwhelmed.
I sold my iPhone and bought a Samsung S6As far as I'm aware it was only 3rd party support previously but now there's official iOS support.
Have you tried the new Cardboard app? It was only released a couple of weeks ago.
https://itunes.apple.com/us/app/google-cardboard/id987962261?mt=8
What is screen door effect?