I had trouble picking a favorite between the PS3 and my iScan (strictly 480p on both).
If anything, I thought maybe the PS3 was a hair smoother (or perhaps softer) looking, but detail was really good. Perhaps it's actually a cleaner image since I have a shorter chain from the PS3 to the TV than with the DVD player.
Great detail, even in dark images and the picture sure seemed rock solid. I was really looking for jaggies and the like, but didn't detect them with the two discs I spun.
Didn't try any widescreen TV shows to see how it will handle edits and switches from film to video mode though. If it's faster at recognizing changes than the iScan I might be using the PS3 a lot more for DVD. Wish I could pillar box 4:3 with it in 480p though. I understand it does it automatically when upscaling it.