Hello, I read carefully all the posts but I cannot make my mind right now about going Mavericks. I've had my 2012 iMac 27/8 Ram/3.2 i5/1To Fusion Drive/ML for 3 months now and ML runs smooth as possible. All is perfect. I'm very tempted to go Mavericks but anxious too. Love the new features in Mavericks. I tend to wait for the next update when upgrades occur. Does Mavericks eat more precious Ram than ML? I read too many conflicting posts about the speed after the upgrade and some compatibility probe with some apps. People here that made the switch and their machine runs flawlessly? Thanks for the hekp and hints.