I use open dental. Tell me how open it is. An open EMR in healthcare does not mean much. Take a look at the necessary support needed to have the proper compliance.
OpenEMR is 100% open source. It's GPL'ed :).
As far as compliance, we are happy to inform you that OpenEMR is now 2014 ONC Ambulatory EHR Certification complete.
EDIT: If you're asking about support, there are over 30 professional vendors. Community support is also available.
If you have further questions, feel free to reach out to my email (in my profile).