PS3 DVD Playback vs. XBOX 360 DVD playback vs. stand-alone DVD player

Recently I did a comparison between a mid-range Sony DVD 1080i dvd player and the dvd playback capability in the PS3. They were both hooked to the same TV through an HDMI cable. My thinking was that the PS3 would be better or similar to the DVD player. This was absolutely not the case: the stand alone player was far superior in details and lack of blockiness that were present in many scenes with the PS3. I would not recommend using a PS3 as a stand alone DVD player and find the small price of a true DVD player worth it. I recall being similarly disappointed in comparisons with the DVD player in the XBOX 360, but I am using component output for that unit.