I've never really understood this. As I understand it, Mixbus is simply the Adour DAW with Harrison's DSP built into the busses. Is there any advantage in doing it this way rather than just using a hypothetical Mixbus plugin which would apply the same DSP but in the DAW you're already comfortable with?
It's not so much as a rant as curiosity. Actually I quite like the idea of finishing off a mix in another program, it's another level of motivation. On the other hand if Mixbus was just a plugin I wouldn't have to learn another DAW.