Music resumes. To go to a screen, it takes about 3-7 seconds once I push a button, depending on the screen. This is all without viz (small viz) on.
The lag was really the main reason I stayed away from RR because it bothered me alot initially. Mediaengine and FP work alot smoother and respond quicker than RR. But once I loaded up this skin and played around, I was locked in. The Flash-based skins REALLY kill my performance, though.