SDE is completely a personal matter. There are guides, but some find it objectionable, and others not at all. The best way to determine your level of acceptance (or rejection), is to demo a projector and move closer/farther from the screen.
If you're an 'experience' type, who likes big pictures, it'll probably be less objectionable. If you're a 'purist' type, who likes ultimate clarity, it'll be quite objectionable. PJ's are like cars in a way - they make lots of models and let the customer self-select what they like and can afford.
I'm a big picture guy who wanted movie size images at home. I self-selected basically the cheapest decent contrast LCD PJ I could find and am very happy. I watch mostly 12 feet wide from 15 feet seating and find the picture excellent. Good DVD material is superb, and "HD" material is even better. Sure there is SDE (and I bet quite a few people would find it objectionable), but a few minutes into the content I forget all about it - because the experience is what I'm after.