Just got my Kingtee 19MB, running OS X Mountain Lion 10.8.3.
Two issues so far: OS X doesn't recognize the exact 1440x900 resolution of the display in the "Display" Preferences. It lists a lot of other options, including 1400x1050 and resolutions that are somewhat close, but not the exact resolution of the screen. A relatively minor problem as it doesn't inherently pose any obstacles, some pixels are just a little blurry.
The bigger problem is calibration of the cursor. Right now I can only adjust the offset of the cursor, which, in one resolution (can't remember which) got the pen and cursor to line up horizontally. However, vertically the distance the cursor moves is smaller than the distance I travel with my pen. Also, the menu bar seems to be out of reach, as well as the bottom of the screen. Perhaps this is caused by the failure to accurately recognize the resolution. Other than that it would be a great improvement if the calibration worked more like wacom did it: http://www.youtube.com/watch?v=tRR6U-5hq6w
Anyway, keep up the good work. It's great to see user based initiatives like this!
Ok, now I'm back home I connected it to my MacBook, and it all works perfectly now for some reason. I connected and reconnected a couple of times, and restarted the driver and now it seems to work perfectly. It recognizes the display's 1440x900 resolution and the cursor and pen actually line up. I guess it was just a bug then, but I'm a little anxious about the next time I connect all this stuff. I'll keep you posted on more weird stuff I might encounter.