The EMR part is not that different. But many EMR are no EMR. They are smart frontends for billing. They don't care about medical concepts like health issues or disease episodes. They don't bother with (S) ubjective, (O)bjective, (A)sessment, (P)lan concepts for the record.
They support one lanuage and one health system. It is the 'not invented here' syndrome that keeps us from using it. No way to switch GUI language or coding systems (ICD 9/10). No way to switch billing engines.
They work well in their health system but nowhere else. That is what we avoid in GNUmed from day one. We have a long way to go feature wise because we make sure that GNUmed can be understood and maintained in 10 years.
We try not to model the database to fit the user interface but use PostgreSQL to make sure that even without a frontend patient data is not only secure but accessible as well.
Features will come quickly if one has a strong base. It's like designing a programming language for a specific application or design a programming language so one can write many programs with it.
So if any one wants to take a look at GNUmed and add billing for the US you are more then welcom.
http://wiki.gnumed.de