I have an early 2009 model iMac that still runs fantastically. I haven't had any issues thus far. With Mavericks, everything is just as speedy and I haven't encountered any major problems, except for one: Maps doesn't work for me. I can't view Maps at all. The application is open and it even finds addresses and my current location, but I don't actually see the map. All I see is the grid behind the map. Anyone else having this problem?