any body use a roland vs-2400 or 2480 w/thier mpc?

if so which do you use as a master?

Use the Roland as the master. What you may need to do though is make a one bar space on the MPC in Song Mode. I've experiened maybe an 8th of a second getting cut off when recording. You can alway go back and chop off that blank space of the roland. Oh, and I got the 1680 but the features are still similar.