What is Opus?
The best-sounding lossy codec at low bitrates by a comfortable margin, which is why it carries the audio in nearly every voice and video call you make. Royalty-free, equally good on speech and music, and usually wrapped in an Ogg container. It always runs at 48kHz internally.
What is AIFF?
Apple's uncompressed format, the Mac counterpart to WAV, and still what Logic and older Pro Tools sessions expect. Its one genuine oddity is storing the sample rate as an 80-bit extended float, a data type almost nothing else in computing still uses.