I've been using this for a couple months and must say that I was relieved to find and open-source medical records program (even if it does require FileMaker Pro, which is actually a good thing, since I'm not about to learn programming again). Now I can tweak the program to suit my needs and not have to worry about the developer going out of business and losing all my records (as well as having to find and learn a new program). It may take a bit of labor on my part to make the changes, but compared to people I know using Windows EMR software (huge, expensive and slow), this is just what I need.
It isn't all things for all people, but it does quite a bit. Frankly, if there's something you need, just add it yourself (or hire someone to do it if you like) and then it can be added in for everyone.
For lots of medical clinics that don't have lots of spare money, this is a godsend. Stefan is working on it in his spare time, and has done a remarkable job.