I would categorize the change from my first projector (720P Mitsubishi HC3000U) to my second projector (1080p BenQ W5000) as noticeable. But only in a very subtle way. I could never see a pixel on my 720p pj unless I was right on top of the screen. If my math is correct there are roughly 15 lines per inch vertically for 720p on a 100" screen. I have a tough enough time seeing a sixteenth of an inch when in the workshop, let alone on my display. 1080p would add ~7 more lines of resolution. On your 46" set, there is roughly 47 lines per inch vertically. I really d on't think you could see those without help. And your 32" 720p display has almost the same amount of lines as the 46" - ~45. If you were to have a 175" screen the viewing height would be 90". With that setup, the 720p lines would be ~1/8". That would probably be noticeable for some folks within 6 feet or so. Again, assuming my math is correct.