Personally I prefer the minimalist UI of Evince.
I typed "fast linux pdf viewer" into a search engine and quickly landed at Okular, which has a setting to prerender everything and keep it in memory. It flies!
MuPDF is by far the fastest, much faster than Okular or Evince, both at rendering pages and at navigation through the document (also the keyboard-shortcut-based user interface of MuPDF is much faster than the more typical GUI of the other PDF readers).
MuPDF has various limitations and sometimes I find certain PDF files that it cannot render, so it cannot be used as the only PDF viewer.
Nevertheless, using MuPDF to handle the common cases of quickly opening, searching and reading PDF files, together with a fall-back more complete PDF reader, e.g. Okular, seems the best option on Linux.
Now, I'd like to see double (facing) pages. And it seems MuPDF can't do that. So I'm stuck with Okular, which is sad, as it's the only reason for me to have QT installed...
For whatever reason, Evince didn't work right for me on the first try under KDE, so I switched to okular, and never looked back. KDE was preloaded on my laptop, and it's tolerable.
I used to use gnome stuff under minimalist window managers, but that's getting harder and harder on laptops, due to strange hardware integrations with desktop environments.
Sometimes I think the year of the linux desktop was 2003. High dpi displays just worked. So did networking stuff and suspend resume.
Anyway, I'll end my rant by pouring one out (each) for xpdf and evince.