In theory...RGB is better. The reason why is that though HDTV is a Component Format your RPTV is using 3 CRT's to produce Red Green and Blue. In all CRT based displays there is an RGB amp. This is the final step in the "conversion" process from which the signal is sent to the CRT(s).
If you start with RGB you have less conversion going on then if you start with any of the other formats like Composite, S-Video or Component.
In the everyday world many times the average person can see no difference between RGB and Hi-Band Component.
Many choose what their display accepts. Some do not have RGB (in the form of a 15 pin "d" VGA connector or 5 seperate BNC's) while others do. Because the 6000 offers both you can experiment if your RPTV accepts both and make the judgement for yourself.
For the RGB test you can use a short (read 6' VGA to VGA computer display cable which are not expensive)
Let us know your findings