Regarding this M-Audio module, I just read in another forum how everyone complains about the low quality of their products, but I think you have to distinguish the sounds (which they get from third party providers) from their hardware.
So, I don't see a reason why the low price alone would suggest a bad piano sample. Listen to the piano at 3:10 in this video - the demonstrator plays a very simple tune, which makes it sound less impressive, but I think the sample itself sounds very good:
https://www.youtube.com/watch?v=ST2Sz-Mujrc
(video posted by Torch already)