You wanted input, you got it.
Cubase 7 has been a CPU nightmare and Cubase 6.5 wasn’t all that great either. Digital Performer 7.24, Digital Performer 8 (which I am seriously considering an upgrade to because of the C7 BS), Studio One V2 and Reaper 4 all run efficiently on OS X; almost on par with Logic Pro 9. Even the Steinberg plugins such as Padshop Pro and Retrologue run horribly under C7, but in the other aforementioned DAW’s they run at about half the CPU (as C7).
What is it that makes it so difficult to find the flaw in C7 where it becomes such a CPU hog on OS X? If Steinberg has really been researching this phenomena for years, and they are still hard pressed to find it, then maybe a total re-write or hire seasoned, experienced OS X programmers is in order?
Time to hit Yamaha up for money for R&D.
EDIT: OS X 10.8.2/Intel C2D i7