Kexts updated so it now supports OS X 10.9.1
Buttery smooth performance, no crashes at all during my 7 day test. Gaming should be fine, I've only tested it with League of Legends at max options, resulting in 60FPS.
Use the latest version of Chameleon just in case.
Tested on a XFX Radeon HD 677X-ZNLC 850M 1GB GDDR5 though it should work on Gigabyte, MSI and Asus models as well.