I hear they're not the best, but pretty good. However I've just got MGS4 and the graphics look really poor.
They looks like the game is outputting in 480p rather than HD, the seems to look more like PS2 level graphics. Nothing like the sharp visuals of all the other games I got.
I've messed around with the PS3 settings changing between 1080i and 720p and neither seem to make any difference.
Also the PS3 hasn't asked me to download any patch or update for the game. Has anyone had any issues like this?