It's been about two years and a major release since I last looked at ExamDiff Pro. This differential program inhabits a narrowly defined niche used by programmers, Web site coders, and others who need to compare different versions of long, convoluted documents. A differential, or a diff for short, highlights the differences between two documents, both from the 35,000 foot view and down to the line and character level of detail. Typically, such a program compares two files, but more advanced differs are capable of diffing three files at once. Differs usually display the documents under scrutiny tiled next to one another, and highlight differences in lines, whole sections of the document, and even character-by-character differences. ExamDiff Pro is perhaps the most versatile such product available.

Unlike version 4.5, the 5.5 version of ExamDiff Pro is not distributed as two separate SKUs, one with and one without the powerful conversion plugins that make this program uniquely suited to diffing the most important parts of documents--the textual content--published in a wide range of file formats. ExamDiff Pro automatically converts the contents of Word .doc, Powerpoint .ppt, and Adobe .pdf to text in order to compare them; it converts Excel .xls spreadsheets to comma-separated value (.csv) files, as well, and can unzip or decompress any file format supported by the program 7-Zip.

Comparing executable files for which you have no source code can be tricky because, unlike document files, applications can use runtime packers that compress the size of the file on disk, and only decompress the program fully while it's running. ExamDiff Pro is the only differ I've seen that can automatically generate a dump of 32-bit PE files so the comparison is as accurate as possible. And ExamDiff Pro also is the only diffing tool I've seen with a so-called Fuzzy Comparison feature, which ignores small formatting differences like line breaks or extra spaces, and concentrates on the text itself.

The only problem I encountered while using ExamDiff Pro was that I accidentally enabled the Sort plugin before comparing two text files. The documents, which were a few lines of code, were sorted into a meaningless list of commands when I did this. Only by disabling the plug-in (click View, Options, then click Plug-ins in the left pane and deselect the checkbox next to "14. Sort [installed]") was I able to view the contents of the files with their lines in the correct order.

ExamDiff, at $35 after its 30-day trial expires, fits nicely in the feature and cost niche between free, but sparse diffing tools like KDiff3, and higher-end tools like UltraCompare. Its ability to generate a dump of a binary file is a nice bonus feature, but not a necessity; Coming up with something that resembles parity between documents saved in disparate file formats, something ExamDiff excels at, is harder and a more welcome feature. For most people who need a diffing tool, ExamDiff will suit their needs most of the time.

--Andrew Brandt