The possibilities are endless, you could use it to emulate guitar stomp-boxes (diode clippers), tube pre-amps (check the examples), implement vintage filters, etc…
One thing that has been particularly fun to me, is to incorporate small pieces of analog circuits in your own DSP algorithms, to give it some analog feel.
When your emulating a analog circuit, the usual variable parameters are potentiometers, and at the moment of writing it doesn’t support that, but I’m working on it.
There’s no performance benchmarks, but according to my tests, it isn’t good enough for production yet. This will be solved using lookup tables for the non-linear system solver, which is also being taken care of at the moment.
As mentioned, the project is still in its infancy, but hold tight that cool things are coming!