Well I have no proof that it has anything wrong with it. But, I figure evince on *nix has a much smaller footprint than FF cross-platform. So, I'm figuring the script kiddies are not spending anywhere near as much time reverse engineering evince for holes.
I'm sure you'll be less vulnerable by far on FF than adobe. But as soon as I read this I went in to my options and changed it back to *asking me* to open PDFs with evince.
I never like it when things happen too automagically: There be dragons and exploitables. Even FF can get hit by driveby downloads.
