I've had some awful graphics issues since the 10.9.2 update. Sometimes Safari glitches like crazy when scrolling or typing in to scrolling text-boxes (e.g. comment box on The Verge, or Apple's own bug reporter form).
Not only that, but if you have two monitors with Safari windows, and one of them is playing a full-screen flash movie but the other monitor has a standard window which is active, the menu bar doesn't appear on the screen with the active Safari window. So if you're streaming a Youtube movie on one monitor, while browsing the web on another monitor, the menu bar won't be on the monitor you're browsing on.
Lots of other bugs and glitches, too. Spent half my day already reporting them to Apple.