I suppose time will truly tell, but I've been lag free for the past 7 days. I figured the mac pro case wasn't entirely at fault b/c I have a Microsoft Bluetooth mouse that pairs wonderfully with it.....So anyway My Mac Pro is wired to an Airport Express, which is an access point for my Airport Extreme. I changed the 5Ghz channel manually to 161 (I already had 2.4Ghz on manual). The Magic Mouse has been solid ever since. Must have been wireless interference.