I use xpdf or evince. Never ran into a PDF that one of those couldn't handle. My needs are simple though.
My favorite PDF reader currently. It's limited, but faster than anything I've tried.
Mupdf searches large pdfs much faster. However since I switched to wayland/sway I also use zathura because cut & paste works. Mupdf is an X application but I still use it to search large pdfs. But there is also this plugin but I did not try hard enough to get it running: https://github.com/pwmt/zathura-pdf-mupdf. Under xorg worked cut & paste with mupdf.
That's not a fair comparison as you need a bunch of dependencies to actually render stuff. On my system zathura-pdf-mupdf alone is 24M.