Problem with Software as a service is that if you rely on obtaining information from a server off-site of the medical facility, you are limited to accessability to external network resources. I know of Hospitals that use offsite servers for their patient databases and they have problems with connectivity and if there is ever a severed connection they no longer have access to their patient data.

We have seen the outrage at having yahoo, google, etc being down. Could you imagine when a life is at stake?