It does look much better on a smaller screen (to me). I have it on my OnePlus Two, iPhone 5s, iPad Mini w/ Retina, and rooted Nook HD+ tablet. The OnePlus Two and iPhone 5 look amazing. The iPad and Nook kinda look stretched and not as clean, but maybe it's just me.
It's pretty blurry on a 7" tablet. There must be a better way to simulate a CRT without blurring everything so much.
It's not made my eyes hurt, but then again I didn't try using it for more then a minute or two.