I have worked on two Allscripts systems - Misys and Ntierprise. The good points are the support, reporting and the autposting. These billing programs did the job but doing some things, like simply rebilling a bunch of claims for a patient has many steps. My general opinion of the two Allscripts systems I have worked on is that they both seemed to be more complicated than needed, but I have also worked on far worse systems. I would carefully go over the demo and consider all the things you need and don't need for your client.
They also try to lock you into using their clearing house. I am currently changing my cleint who uses Ntierprise from the Allscript's clearing house(Navicure) to Office Ally (it's free).
If you have more specific questions I can answer feel free to email me.
Lisa
Lisa@srts-inc.com