Tool for creating compact diffs for binary files

Hello.
I would like to integrate an effective patch building (producing very compact differences) for binary files into my application. Recently I have found a nice solution – DF SDK by Agensoft (http://www.agensoft.com/dfsdk.html). Downloaded a free Demo – it works fine for me. The DF SDK itself is provided in the form of a single DLL which also suits my needs and moreover – as it is written on the authors website – they are giving a 200$ discount till 15 of December.

Could you please share you experience on this software product or even suggest another noteworthy solution (sold at a reasonable price).

Thanks in advance.