The interfaces

Dotfuscator Professional

Dotfuscator itself is a command line tool, but through the interface shown above, and the resulting XML file it generates, Dotfuscator gives you complete control over how and where it applies obfuscation - although in most situations everything should work fine without any tweaking whatsoever. When renaming identifiers, you get a choice of what classes to exclude, and options such as adding your own custom renaming prefix and changing what indentifiers are renamed to - be it numbers, alphanumeric or unprintable unicode characters. My only complaint about this interface is that it feels a little antiquated, and browsing for a folder is far more painful than is necessary in this modern day! Obviously though, once you've chosen the options you want, you can call dotfuscator automatically from your build process and simply pass it the XML configuration file.

Demeanor for .NET, Enterprise edition

Demeanor is also command line based, but includes an additional program that can be used stand-alone or as a Visual Studio .NET add-in, and like Dotfuscator, uses an XML file to store configuration options. This makes the obfuscation process a little easier to integrate into your existing build process if you're using Visual Studio.

Conclusion

Both of these tools provide significantly increased protection for your source code - and I have no major complaints with either of them. Demeanor provides slightly less control over its behavoir, but also seemed to work first time more often than Dotfuscator. In the end, the decision will come down to you deciding which of the additional features you find most compelling. Both have a large price tag, although there is also a "community" edition of Dotfuscator available with a more limited feature-set.

(prices are correct at time of going to press).