VCAST Music Disables MP3 Playback

A big question is ... how much loss is there going to be when WM10 converts an MP3 to a WMA? I understand some people can tell the difference no matter how small the loss is, but I think if we get it out in the open the actual quality loss in hard numbers then people can make a determination to see how it affects them. SystemShock seems to be up on this since he is debating it so much, please inform us of the loss of quality, I can't find it anywhere on the internet how much quality is lost...

Is it like Black and White or Black and just one shade under Black so most people (target customers) can't tell the difference?