When the initial announcement of the PolyBrute came, I was quite upset at first. But after watching all the demos, and most importantly, playing my MB again (!), I realized that I don't really need the PB. I love playing the MB for what it is, despite the remaining bug(s), etc. I have spent a long time discovering it and developing a really productive workflow on it, and even a (highly improbable) trade-in would inevitably set me back with another learning curve. At my age (!) time is the essence, and constantly learning new instruments gets in the way of making music...
That being said, if I were to acquire another poly, it would probably be the Hydrasynth. I think it sounds fantastic (digital, yes, but different) and has super expressive capabilities with the poly AT, long ribbon and macro controls. The Daniel Fisher demo was very impressive. Here in Montréal, the Hydrasynth is roughly half the price of the PolyBrute...