The Sketch 3D apps function like the iKaossliator app with the important addition of being able to import your own samples! Once imported you can go nuts with a number of interesting ways to play with them and blend them together. There are a lot of creative sound design options available, including morphing between samples, which can be a lot of fun. Unfortunately the whole experience is marred by a terrible interface and a lot of graphics bugs. As of version 1.2.1 the interface has been updated, but is still pretty ugly. There is also a crash bug if you launch the online help page. The difference between "Sketch Synth" and "Sketch Sound" is the MIDI and OSC support available in the "Sketch Synth" app.
Disclosure: I received my copy for review from Shape of Sound.