I am developing for the project Zynthian. Zynthian is a modular software synth based on Raspi and famous engines like ZynAddSubFX, setBfree, Fluidsynth and others.
Currently we are using Hifiberry soundcards but the pisound looks very promising for more functionality . Especially the line in would be a very nice feature - so we can use vocoders, effects for guitars and voice, ...
I hope I cn get a pisound as fast as possible because we would like to use it for our showcase on the next Maker-Faire in Berlin.