Chris,
We use Lytec but don't interface to Amazing Charts. We've played with Medisoft. They're BOTH supported by NDC, who generally aren't great in the support department. From a support standpoint your best bet is to partner with a local VAR, and buy the software through them AFTER getting and checking references regarding their support capabilities.
Our recent update of Lytec was about 4 grand - not cheap.
Good luck,
V.
