I'm a user of CS5, on a MacPro.
I was so disappointed with the amazing slow responce when trying to use the Mixer Brushes; fine when using small files, suitable for web, but when working with larger files intended for large printing, it was painful!!
Have the people at Adobe sorted the problem out with CS6?
It seems that many experienced user contribute their time to giving there thoughts and findings on CS6 and would like to know their toughts on the question above! Please?!
I guess that will depend on your machine and the size and kind of Brush tip you use.
With large Bristle Brushes I do get somewhat of a lag.
But maybe you should ask over at
or just try the public beta.
Still seems pretty slow.
But keep in mind I'm not testing with a system that can take advantage of all the possible GPU enhancements such as OpenCL (though I have no knowledge that the Mixer Brush CAN use the GPU in that way).