Well, it's slowly getting there. The first public release (0.1.0, released 07DEC98) was very rudimentary and contained lots of bugs.
As of release 0.2.10 (relased 07APR1999) things look a lot better: Terraform is now a lot more complete and doesn't crash as much while having gained lots of functionality.
As of release 0.3.1 (released 23MAY1999) things look better again. The dialogs have been upgraded to a real time preview dialog and I've fixed quite a few bugs, some of which caused seemingly random crashes on some platforms.
As of release 0.4.4 (released 28OCT1999) we have a pretty complete set of dialogs and an engine that can keep mulitple height fields open in parallel.
As of release 0.5.0 (released 20DEC1999) the source code is a lot saner/cleaner and terraform now supports internationalization.
The current version (0.4.4) should support more features and hopefully less bugs.
It's come quite a way but still has ways to go before I have it doing what I want. Please realize that I have a job and a life and that I'm writing terraform after work at night or on weekends. As such my progress will at best be steady but certainly not lightning-fast.