They're kind of like ISO+WAV images, but instead of having an ISO for the game data and then a WAV (or the dreaded mp3) for each audio track, there's a BIN for the game data and then a BIN for each audio track. Images consisting of multiple BINs with a single CUE work the same way as an image with a single BIN and CUE, and has the same compatibility with stuff like ImgBurn and ODEs. If you're downloading, the newest trend for 'best' image format is multiple BINs with a single CUE.
If you're backing up your own discs, just stick to the BIN/CUE format.
