I currently own an Alpine 9825 cd player (does not support for mp3) and it sounds great.
Initially I bought the 9826 (cd/mp3 model) but ended up returning it for a 9825 because cds sounded better (clearer, tighter sounding with more bass impact) with that unit. Since both units came out at the same time I doubt the difference would be in the QUALITY of components used. Perhaps the 9826 uses a different laser which isn't as accurate as the traditional laser used in the 9825, or maybe it overprocessed the cd sources.
A few years later I bought a newer Sony (and another Alpine cd/mp3 head unit) mainly for the USB support. The Sony was the biggest pile of junk I have ever heard - fidelity was terrible, the newer Alpine (9883?) was definately better than the Sony but no where close to my 9825 in terms of sound quality so back it went! But the older 9826 model definately sounded better when playing mp3s compared to the newer 9883 unit.
Has anybody else found cd players sound better than cd/mp3 players? I know a huge proportion of car audio people have mp3/dvd compatible players in their cars.
I would like to add that I didn't change any other component in my system apart from the H/U when comparing the sound quality.
Also the speakers I am using are Alpine DD Linear 6.5" coax connected directly to the H/U but that is not the main point here.