WTF? ONLY two oscillators? Don't think of it that way as with the zillion programmable envelopes and shifting waves, it sounds thicker with one oscillator than many with three. This is the synth the Waldorf XT and Ensoniq Fizmo were trying to be, but is magnitudes ahead of them.
This is the perfect "desert island" synth. Unless you are immortal, you will NEVER even scratch the surface of this tool. Yes, it is deeper than Rhino and Absynth (also two very fine instruments).
What is seems to do best at is incredibly moody pads and otherwordly soundscapes and effects. Kubik is perfect for painting sonic pictures and while it can do "standard" synth sounds and has a full complement of modulation controls, is not the one you would likely reach for as your main performance synth.
Kudos to the author for creating a v-e-r-y different kind of synth that will never grow stale. You will be amazed each and every time your explore this beast.
For all it's massive firepower, the CPU hit is lower than expected and is quite stable. The layout is pretty straightforward and has a clean and usable look. With most synths, I have a wish list and mine on Kubik is very short: add more tools to make it easier to dive into.