A large part of success/failure is that someone of authority in the practice has to take accountability to direct all the physicians that EMR is either go/no go for the entire group. This is not to say that leading physicians through the buy in process is not vitally important, only that the organization cannot be divided once an implementation decision has been reached. The single most important factor leading to dissatisfaction is allowing physicians to dictate when they will or will not join their peers in adopting EMR within the same practice. A physician champion is needed to make it happen but everyone has to hold hands and jump into the cold water at the same time.
When done right, meaning a complete reengineering of internal processes concurrent with the installation, not just forcing the EMR to mimic "the way we've always done things in the past "goes a long way to realizing acceptable advantages. The monetary challenges and ramp up time will, however, still remain difficult for most.