I am a solo provider too. I just signed up with http://www.mtbc.com I have heard very good references about this company from different people using Amazing Charts. It is too early to say about collections, but so far I am very satisfied. I export superbills directly to MTBC. In less than 48 hours all claims submitted appers on secure MTBC website. I get daily online notifications of any deficiencies or corrections needed to process the claims, and I make corrections online. I can monitor status of each claim online.