On OiNK, if you want to upload a perfect copy of a CD, they ban RAR'd ISO's, which to me makes no sense. They make you do a FLAC encode using Exact Audio Copy, under the justification that it makes the smallest files with no loss.
But I've measured RAR'ing an ISO copy I make from a CD, and it's only about 10% bigger than the FLAC hassle. Even EAC says it makes "just about" perfect copies.
But an ISO *IS* a perfect copy, isn't it? What is the justification for all this FLAC nonsense and opportunities for CRC errors just for 10%???