I didn't care for the Winduhs player, and the MusicMatch bundle that came with my machine wasn't all that great, with it's unceasing "upgrade" boxes and how it dropped the master volume and .wav volume whenever you closed it. I found Winamp to be a good alternative. Still is, compared to WMP9, which wants to connect to the web to find codecs to play things that 6.4 can.
I noticed an mp3's quality depends largely on it's bitrate, the codec used to mp3 it, and the quality of the machine it was mp3'd on.
Oggs tend to lose quality in it's compression but tend to keep goo high and low end tones, it's the midrange on them that suffers.
I have a few mp3's that have a bitrate of 320 that I 'ripped' myself using Winamp 2.91 and the Lame encoder, and you can't tell the difference between them and the original CD.
At around 196 bitrate you will notice differences..
People with better ears than mine can notice a difference at 225 bitrate.
*sigh*
But I can hear dog whistles.