I worked on a project today that required incorporating two technical datasheets into a PDF portfolio. One datasheet was given to me about a year ago. The other was given to me today. Other than the data in the top right hand corner, both pages looked roughly identical.
Now, I have come to realize that I have a high tolerance for digging through monotonous details. However, this project was on a deadline, and if I tried to compare both documents manually, the changes are fair that I might miss one of the minuscule details.
However, a few months back, I was fortunate enough to beta-test a new PDF comparison utility, by PreMedia Systems. PDF Comparator examines the PDFs, pixel-by-pixel, and instantly display the results. So it was easy for me to determine that there was more differences in these two files than just the date in the top right corner. This utility only works on OSX (as opposed to Windows). Awesome tool! Check it out.