An "extra quality" pack has a Clean ROM database checksum (CRC32/MD5/SHA-1) for every single file.
: These are significantly larger files (sometimes 100GB+) because they replace original game music with CD-quality audio and occasionally add full-motion video (FMV). all snes roms pack extra quality
Custom graphics that fill the black bars on widescreen TVs with SNES-themed artwork. An "extra quality" pack has a Clean ROM
An "All Roms Pack" can be messy. You might end up with three copies of Super Mario World (the Japanese version, the US version, and the European version). the US version