Eclipse was chosen as an industry known, open source IDE that we can simply expand with our plug-ins for the debugger /firmware upload features. So it’s free for all to use.
Expanding an existing tool enables a faster time to market, whilst also presenting a familiar interface for existing Eclipse users again making the learning curve for these new devise shorter and shallower.
If you are looking for a more mature environment, please see the tools available from MikroElektronika. They will provide hardware and an IDE (Integrated Development Environment) for both the FT51A and FT900 devices.