There are several others like eClinical in wide use. Depends on acute/outpatient etc. Open source is more a less a losing proposition for a mainstream EMR because of certification and integration requirements that amount to at least hundreds of thousands of dollars per year. ClearHealth was, as far as I know, the only open source EMR ever to have surescripts and full federal certification. It cost us about ~2 million a year to maintain all that.