CDP choices-Looking for advice

Hi everyone,

In the market for a new CDP for my 2-channel setup.
-95% redbook playback but SACD and BD would be nice bonus as a all in one unit. I will also need to address video options aswell for watching mostly concert DVD's
-I do not want to sacrifice 2ch playback with a universal player.
-Budget 1500+/-

Players/scenerios under consideration.
Oppo 83SE-bang for buck award winner?$900 roughly
Marantz SA8003-Price is right+Oppo 80 or 83 for BD $1300-$1500
Marantz SA15s2-Sure looks sweet+Oppo 80 or 83 for BD $1700-$2000

Is there that much of an improvement on redbook cd's as I go up the scale?
I understand at some point there is diminishing return, just not sure where that is in this line up.

Thanks for the advice!