The major drawback of this system is that it is essentially an ASP. Data does not reside with you. You have no control (except perhaps through entensive extended legal proceedings) to get your billing data in an usable format. So what if you inputed all of your financial data into this software and they stated that they were bought out by Emdeon and Emdeon is charging a $30,000 a year fee? Can you afford not to have access to your business data?
You have to have something to fall back on when the internet is not working. What happens when your subscription (currently free) runs out?
You know, I could create a website promising return on investment, prosperity, happiness, sunshine and eternal life?
"How many lightbulbs does it take to screw a physician?"