Not being a skeptic necessarily, but how close are you to that TV set. If you are several feet back, with only a 40" screen, I would have to think that a lot of your perceived difference over a 1080p set would have to be the placebo effect. Now, if your sitting 2-3' away, I could see how you could tell.
That post doesn't answer my question. Your later post does. Get the Black Friday Samsung SUHD. You won't be disappointed in the upscaling and you will be ready for 4k content when available, or if you get faster Internet. (Samsung has an upgrade feature for future refinement of the standards.)