If it's per month, I may just keep my current PM system and not rock the boat in the office.
Out of curiousity are you doing electronic filing of all bills and if so how much are they charging you ? You would still be able to use AC's PM and export to a different clearing house or print bills - it is just that the clearinghouse they supply would be 150 per month. I pay around that much for Medisoft and get horrible support as I don't pay several hundred yearly for support. I also don't get real time checking of insurance, etc.