I've asked similar questions before. I'm not an expert on the matter, but let's see if I can explain a little.
First of all, the ISO format should
not be used for CD based games. It cannot handle the audio on it's on which is why you get ISO+mp3 which also needs the CUE. It also has a good chance of "breaking" the image. People tend to favor this format because they hear "ISO" and think it's good. ISO should only be used for DVDs.
When you rip into IMG/CCD/SUB you have the option of also creating a CUE. This format became the standard for PS1 images because it is capable of copying the disc with out breaking the protection. I've ripped PS1 games straight to BIN/CUE before with out any problems though, so I'm not sure what the big deal is. I've never been able to get a clear answer on that. What's more, I've also re-ripped CCD images to BIN/CUE a few times with out any problems.
I guess if you wanna stay on the safe side, go with CCD. From my experience, BIN/CUE is alright. But definitely stay away from ISO+mp3.
ThrashOmen wrote:And what is the best format of these three?
Are you asking for PS1 images in specific or for ALL games? It seems different systems can have different chosen formats. For example, PS1's format of choice is CCD. Saturn, Sega CD and others use BIN/CUE. Dreamcast uses CDI. Et cetera.
ThrashOmen wrote:I'd think there was someplace where I could find perfect dumps for games on the internet but I've given up.
Underground-Gamer
ThrashOmen wrote:What does mounting games to a virtual drive do exactly?
Mounting an image to a virtual drive allows you to use the image as if it were a physical disc. Some emulators allow you to load an image with out having to mount it in a virtual drive.