Can someone explain how this is different from vsig?
With VSIG, you have a fixed (though admittedly large) number of dsp, maths and other blocks that you can wire together to do things. There are some things that are hard or impossible to do with those blocks (notably sample level manipulation, unusual filter design, some non-linear processes).
~gen and ~rnbo are supported in Max that have a different set of tools, so some things that are hard to do in VSIG are easier to do. Conversely some things will be easier in VSIG than in ~gen or ~rnbo. The programming in Max compiles C++ objects that get inserted into the H9000 and can do some custom dsp processing.