All these formats, IFF, AIFF, and RIFF, use named chunks for organization, and store PCM basically the same way, though there are other payloads possible.
My post was BS. The reason Macs became ubiquitous in audio had nothing to do with file formats and likely had everything to do with pro audio software and hardware developers that initially ignored Windows and PCs, and by the time these became platform independent, Mac was too ingrained to be dislodged. But AIFF does have smooth and sexy contours compared to WAV's clunky aesthetic. There I go again.