Depends on the players! But generally, yes, as Nuck says. Some of the better universal DVD players do CD very, very well, but even those can be bettered by a high quality stand alone CDP.
Tommy, the step up to a dedicated cdp is a big one. If the rest of your kit is 'normal', then the step may not be beneficial. The kit is only as strong as the weakest link, after all. A really good cdp may expose other links in your syste.. The whole thing really has to work togethre, after all. The synergy of the system can, or will, expose itself with focused listening. It is all about the music, after all.
And I never see the sign to turn untill it's way too late...