I can speak to the appropriateness of using the platform (Linux, AOLserver, tcl, ACS, PostgreSQL) to deliver a customized database-backed application: it is superb. Rock solid components, very good performance, tons of power and flexibility, a wide open space for you to add whatever specific application functionality you need, technology that lends itself to relatively rapid implementation.
But of course, you need to be a good software developer to pull it all off - IMHO this is not for beginners. I built a binder of crib sheets with about 20 different topics (SQL, tcl, AOLServer tcl functions, Linux commands, bash, emacs, SQL, CVS, SSH tools, ...). And you'll need to feel comfortable digging into the ACS code to figure out what it does.
There have been several good discussion threads about advantages of the platform - look for them in the forum.
