I've always liked the ability to mix waveforms within an oscillator, rather than just select one. Considering the limitations of an analog oscillator, it does increase the tonal range a bit.
Not sure how familiar you are with the previous Brute's but it's not just that you can mix the waveforms. Next to traditional PWM there are different ways to modulate/shape the other waveforms (taken from the Minibrute product page):
Saw - UltrasawUltrasaw provides shimmering sawtooth waveforms that will considerably enrich the sound.
It basically makes two phase-shifted copies of the raw sawtooth waveform. The copies have ever-evolving phase shifts of their own, and when mixed with the original sawtooth they complement one another.
This results in a lively, rich, bright ensemble effect that can be further enhanced by the modulation rates of the phase-shifted copies. This is the first time a feature like this has been offered in an analog keyboard.
Triangle - MetalizerThe Metalizer takes the basic triangle waveform, “warping” and “folding” it to create complex, jagged waveforms that are rich in high harmonics. This results in pitched, “metallic” sounds that are ideal for harpsichord- and clavinet-type tones. Dynamic modulation of the warp/fold parameters by an LFO or envelope opens up a realm of “clangorous” sounds that will cut through your mix nicely.