VA VistA is the top solution for open source hospital systems. There are two important companies in the space, Medsphere and Blue Cliff.
The new Medsphere team has been coming to speed. Earlier at TEPR, they announced that they will be switching to a MySQL-inspired dual-licensing model, as well as changing to the Affero GPL. They have already updated medsphere.org downloads, to match the new licenses.
Much of what had held back the OpenVistA CIS from being the “compelling CPRS replacement” that the VistA community needed was its previous bastardized MPL badgeware license. The current AGPL license closes the ASP loophole for the code, and contains an advertising clause that is more reasonable.
Midland, Medsphere’s first real client, was awarded the HIMSS stage 6 recognition (basically means they are “really exercising” the EHR), and Medsphere CMO Dr. Edmund Billings showed some pretty compelling slides indicating that that Midland accomplished this at a price point and timeline that no other Stage 6 hospital can compare to.
The majority of the employees of the current incarnation of Medsphere are relatively innocent of the bone-headed decisions that the Medsphere BOD has made in the past. However, it is hard to underestimate the bone-headedness of those decisions. From a technology standpoint, Medsphere is essentially back to where it was the day before Steve Shreeve left the company. It has a competent VistA delivery team and is about to beta test OpenVistA CIS. That lawsuit was an expensive mistake.
The only other VistA implementer that I consistently hear good things about is Blue Cliff. There are a handful of other VistA shops out there, but personally I would probably only trust a hospital to either Medsphere or Blue Cliff. They both have the depth needed to pull off a full implementation.