Everything I am about to say is only applicable if you're using an HDTV, which I assume you are. If the old DVD player isn't HDMI there could be some video quality implications, advantage to HDMI. Additionally, depending upon how you have everything set, the upscaling will be different. I'm not that familiar with how good of a job the PS3 does upscaling DVD's, I'll have to defer to other's on this, but I assume it probably does a better job than a receiver or TV would down the line (there are technical reasons for this pertaining to how DVDs are encoded that you can read up on if you're intersted).
