Adobe's PDF Reader is the gold standard, but my netbook is too slow to handle it. I need something faster. What's holding me back is all the security problems with alternative PDF readers.
But then security is not a decision factor anyway since both Adobe PDF Reader and its alternatives are vulnerable. No PDF reader does automatic updates right. And many holes are left unfixed anyway.
Foxit Reader is the most popular alternative and I've had some experience with it already. It's fast and light. It display just about every document correctly.
Foxit Reader can be configured to automatically install patches. I am not sure how well it works. Let's hope I won't get hacked just by browsing websites.