Hi aouimet,
I don't know the recording quality of either of those CDs. However, if you want to test your XBox360 as a CD player, use a CD of known excellent recording quality. The one I used for years for speaker tests when I was an AV magazine editor, was Dire Straits' "Brothers in Arms". I think the track was "Ride Across the Water."
In theory, playback of CDs from your xbox shouldn't differ from any other well-designed DVD player or CD player. Try the playback using the digital output as well as the analog outputs. (I don't own an xbox so I don't know if it has those outputs.)
Regards,
