I think if you have an external scaler, you might want to go with the 970, since it passes 480i over HDMI.
But I think the original 971 would be more suited for you; it's got much better video processing for digital connections, which I assume is what you're using.
I mentioned it elsewhere that I read that Oppo is planning a "new" version of the 971, which will have HDMI out, SACD support, and will be black in colour, but all the same video processing that made the original 971 such a hit with people. Depending on your tastes, you might want to hold out for that, which is supposed to be released late August.
cheers,
supervij