Suggestions for a free PDF Reader ?

A Guy said:

Adobe reader is also a common attack vector for malicious code. Especially if not kept up to date. A Guy

That's the main reason I quit using it and recommend other options ...

Sumatra is what I've been using for years. But, before installing it for others, I ask them if they ever type in fields inside a PDF. If they do, then I don't install Sumatra.

Sumatra can be installed along side of other PDF readers. If another reader is detected during installation, then Sumatra does not try to be the default reader. While I was deciding if I wanted to switch to Sumatra, I used Adobe and Sumatra at the same time for years. (Mostly using Sumatra to read e-books. Drag/drop the book onto the Sumatra shortcut and the book opens to where you left off.)

Here is a post talking mostly about the size of Adobe's reader vs. Sumatra...
Printing pdf-files
... but I also illustrate the "editable fields" issue.

One other minor feature that I miss:
Adobe can print what you see; Sumatra does not seem to have that feature. In Adobe, you can resize/reshape the reader's window so that only a tiny portion of one page is showing (think coupon). You can also enlarge/shrink what you see - then print only what you see. With Sumatra, I have to print the entire page.