Pros: I started using SumatraPDF quite a few versions back and deleted the Adobe Reader, which had occupied an incredible amount of drive space, not to mention RAM. Sumatra is small, fast, uncluttered, easy to use and perfectly reliable. The 270 PDF files on my hard drive, most of them music scores, load very quickly with good rendering. This app certainly makes life a lot easier!
Cons: None whatsoever!
Other Thoughts: @other human: I haven't found it necessary to use an 80 before that six-character hex code. The one for mine looks like this in the config file: #ffe9b6 , and on my system it produces a nice tan background which is easier on the eyes than blazing white.