If you have a fixed panel display (LCD, DLP, LCoS/D'ILA/SXRD) then almost certainly a DVI input would be best. Not 100%, but very close to it
For CRT-based RPTVs it isn't quite as clear cut -- in most cases I suspect it will have a modest advantage in that the input would not need to perform an A/D conversion.
Even component inputs are given an A/D conversion so that all processing can be done.
So, whether DVI is better or not is going to depend on a few things:
1) Quality of A/D conversion in RPTV
2) Ability to access color decoder on DVI input to insure color accuracy.
If 2) isn't true, then you might be better off with component.
OTOH, if you are using a scaling DVD player, most require DVI output to watch the scaled image.
Regards,