CounSol is a standout choice for solo clinicians who desire the ability to customize. In 2015 they introduced electronic claims filing and now also feature integrated ERAs.
One of the most impressive aspects of PSYBooks is that it has come out of the gates with ERA functionality. Most applications have added that long after launching since it can be one of the more complex features to implement.
TherapyNotes is a solid contender for those desiring a user-friendly, efficient system and willing to wait for a full-featured Client Portal.