It is perfectly fine to use a DVD player to play CDs. I personally use a separate CD changer because I do not like the slow loading times of typical DVD players, and I like using a changer to play long pieces of music that continue on multiple CDs. With a DVD changer, typically I would have a longer pause between discs while the player loads the disc. As for sound quality, for you to accurately test that, you would need to level match the different players in order to have a meaningful test. Otherwise, because human hearing is not linear, if one is very slightly louder than the other, it will subjectively be heard as having more bass and more treble, and will often be described as being "fuller", "clearer", "more detailed" (of course one can hear more details if it is a bit louder!), etc., but often will not be noticed as being louder. This aspect of human hearing is why old stereo receivers typically had a "Loudness Compensation" switch that boosted the bass, and usually the treble as well. You can hear the effect for yourself simply by playing with the volume control when playing music that has plenty of bass. As the volume decreases, the bass appears to diminish faster than the midrange, which is simply the result of human hearing being nonlinear (hearing midrange has greater survival value than hearing frequency extremes). Most audiophiles do not bother to level match equipment, and therefore their listening tests are meaningless because the difference perceived, even if real, may simply be a slight difference in volume. Assuming that your equipment is not malfunctioning and operating in accordance with its specifications, it is doubtful if you would ever hear a difference between your current DVD player and other players with typical recordings if the players were properly level matched.