I had dinner with some of the DrChrono guys. I think they are working on security issues (which, honestly, lag far behind adoption as a concern; they meet some minimal standard which is technically HIPAA compliant and better than most small practices now.)

The biggest security concern for something like DrChrono IMO is availability; they do a better job of backups, DR, replication than a forgotten windows box running filemaker in the closet of a small medical practice, now.