ROM/ISO Revisions (Rev A, Rev B etc.)

[realiticness2]

I have a question about rom revisions. I know these mainly concern the NES/SNES games and I think these were re-releases from the developers to update the game in question if it was too bugged (especially game breaking bugs). Want I want to ask is, are these just patched versions? Can I assume the highest number/letter in the Rev to be the most updated version and stick to using that? (Also is there any place to find changelogs?)

Alternatively, is there any differences between game content of these revisions?

[Supreme Warrior]

Very few games have any real changes when a game has a revision, Silent Hill 2 PS2 was one of them (added new content).

most games just get a new serial when they become a Budget title (Greatest hits/Players Choice/Platinum hits/Etc.)

[Retro_Gamer]

Software companies have different reasons for revisions, sometimes to add new content (as SW mentions above) quite often it's to fix bugs in a game. You've probably noticed NES/SNES ROMs of the same game with different versions, and chances are a person could play both versions without ever noticing any difference or rhyme or reason for revision, but even console games can be buggy, even if they had to be played unorthodox like to discover whatever bug. In games like World of Warcraft revisions or patches often fix code where the game can be exploited, or played in a manner not intended by the developers.