Upsampling vs Oversampling vs No Oversampling?

I was just wondering what are the general differences in the sonics of cd players that use upsampling as opposed to regular oversampling are?
Also, how do the sonics of the older cd players that did not use either oversampling or upsampling compare to the newer ones that do?
Which do you prefer and why?
Thanks for your answers.
There no Oversampling versus Upsampling. You would always have some Oversampling whether or not you Upsample.

Oversampling is part of the process of converting digital information to analog sound.

Upsampling is totally in the digital domain where the digital data stream is basically converted to run at a higher frequency.

Here's a primer on the maths.
Now you can ask about CD players that Upsample against those that do not.

The data is the data. What is there is all there is. Upsampling does not uncover any new data. It basically stretches the data to a longer word length by estimation, by using all kinds of fancy math equations.

For me, I only care how the player sounds. How it gets there, whether it Upsamples or not I do not consider much. I do not think one way is always superior than the other.
hi daltondanny:

why not do a comparison for yourself ?
Audio Research built two versions of their CD3 during development. One of them used upsampling, one did not. After evaluation, they ended up building the CD3 with no oversampling.