It also depends on the size of your screen, how close you sit to the screen*, and whether your display is calibrated or not.

*I notice more compression artifacts when viewing something full-screen on my 17" laptop display than on my 20" CRT or my roommate's 80" HD projector screen, and the main reason is because I sit about a foot away from my laptop's display, which means the screen fills more of my field of vision than either of the other two displays I mentioned.

Basically, if you have a small screen or a big one that you sit far away from, and/or it is calibrated or too dark, you won't notice a difference. If the display is too bright, and/or you're watching on a large screen that fills much of your field of vision, you might.

Then again, I get taught in school how to notice these things, so I'd venture a guess that you wouldn't notice a difference between the two no matter what.

Besides, what's the bitrate of the retail GOUT discs?