Are the Game Downloads visibly better?

I have not noticed any difference, besides the noise factor. Of course, I believe if you had a scratched disc, it would improve. If I have a good disc however, there will be no performance boost.

I have tried plenty of games, the one I was hoping would improve or at least notice a difference is Two Worlds. That game has terrible performance issues, I thought my terrible frame rate might be due to the disc not reading fast enough. It didn't make a difference. I have tried other games as well, I have not seen a difference in loading times, or anything else.

Basically I would use it for a scratched disc game, or if you plan on playing a certain game for hours on end. (Easier on your console.)

the loading times usually decrease when you install the game (cept for halo 3 unfortuantely)

and (in my case at least) it keeps the dvds from being so scratched up that you can't play them