I've tried the Kenko DG set for AF cameras, but AF doesn't work. In fact, once you open the box, it says to turn your camera to MF mode.
Ok, yes, I know that Macro work is mostly done with manual focus anyway, but it's a weird thing to put on a box
Auto aperture works fine though, and the focal length is transmitted to the camera.
The Vivitar AT-22 comes in two models, one which has the AE (auto exposure) contacts and one which doesn't. Otherwise, these work the same as the Kenko ones.
One weird thing is that SDM lenses (well, the DA*55 at least) can't be used with either of these tubes. The shutter speed varies wildly, the display on the back looks like you're trying to press the ok button constantly, and live view won't work.
I also have the Kenko Uniplus 25 tube. It preserves auto-focus and auto aperture, and works fine with SDM lenses. Wish I had the 12mm version, but it's really rare!