I also think there's a bit of pot luck with the lens quality. My first Rift CV1 had some faint green lines across my view, and I very nearly decided that it was ok and I could put up with it. But once I'd spotted them I couldn't 'un-see' them.
I returned it and got another one, and the view was excellent. I can't say I saw much SDE in race sims or any other game.
I later tried someone else's rift, and it had a sort of 'film grain' effect across the whole view - maybe that's the screen door effect - it was nothing bad, and I would have considered it perfectly acceptable if it had been my second Rift, but it was noticeable compared to the clear lenses in mine.
The single most important component in the headset should be better quality controlled, & should be of far more consistent quality than it actually is.