ZIPs
because then I can undo mine and fuck ur mum
ZIPs are pretty basic filetypes for compressing downloaded software or files. PDFs are mostly used for text-based documents and scanned images. They each perform different tasks, so there's really no comparison between the two.
Personally the only real time I've needed PDFs were in college, and that was 7 years ago. My workplace regularly sends out PDFs with obnoxiously-formatted instructions on price changes or promotion setups but I'm not sure if I should count that. Otherwise I mostly use ZIP.