I have narrowed my choices for a progressive scan DVD to these two based on all the positive reccomendations from each of you. I will be pairing it up with a Pioneer SD533HD5 upon delivery. (THANK YOU JASON AT ONECALL!!!) What (specifically) are the differences? (I know price is!) I am on a budget, so I am trying to justify paying the additional $$$ for the RP91. What does it have/do that the RP56 does not? What will be the difference when paired with this RPTV, which already has an excellent line doubler? Thanks in advance for the time you shall spend anwering my questions!