Sometimes less really is more and Sumatra proves this.
Small, powerful and light, this free open source program works with many formats – PDF, XPS, eBook (ePub, Mobi), CHM, DjVI and Comic Book (CBZ and CBR). Its interface is clean; a simple toolbar and the ability to pin reading material to the “Frequently Read” front page are helpful touches.
Portable, there are no dependencies so you can run it easily from a flash drive, but either way it’s lightning fast. Fast to open, fast to load and fast to search files. You can even quickly search text within files and attach any file to an email you might want to send. It even comes with a manual and the site offers an entire page of keyboard shortcuts.
If you uninstall it, Sumatra is courteous, leaving only a folder behind; however, I reinstalled it immediately because I’m spoiled now and nothing else will do.