I just got a Revo premier, this is the first reel I have had with a magnetic brake.  Is there anything I should know before I get a huge overrun?  Just wondering if there is a major difference in how to cast with a mag. brake v. the centrifugal brake.

PM Micro he is the Revo Brake Expert!!!!

Expect some overruns until you get used to it, and until you find the best settings.  

IMO, the best way to start out is to adjust the spool tension knob until the lure falls very slowly, perhaps requiring the slightest jiggle of the rod tip.  Then set the brake to about 50%.   I think this is a good starting point.  Adjust as necessary.  

X2 with what micro said. I did exactly that last year and it worked well for my applications. The few overruns that  I had were bc of operator error, ie. switched to a lighter lure w/o adjusting. Good luck

If you ever take apart your reel to clean and oil,never ever get any oil on the magnetic assembly. it wont work properly . Keep it dry>