I personally have used several billing software companies and have thought each one of them left a lot to be desired. That includes my current PM software which is CollaborateMD.
The bads: No interface to AC. The eligibility checker is poor at best. It prints horrendous looking patient statements. You can only have one patient opened and others can't even access the patient as a "read-only". It's sometimes quite slow and depends on the speed of your internet. It's a monthly $200. The code scrubber is a waste of money and time. Electronic EOB's are difficult to read.
The goods: A million different reports can be pulled. McKesson is the clearinghouse and is quite good considering how massive it is. Doesn't take long to learn. The company is responsive to problems/questions. ERA is easy and intuitive.
Find something cheap (Office Ally) and hang on until AC comes out with something.