I have the Kenko set of 3 (12, 20, 36 mm) for A-mount (Konica-Minolta / Sony)
They work like a charm and feel very sturdy.
I also have a Rokinon 25 mm, which by the looks of it is also a Kenko, but with a different brand name on it.
They all maintain full automatic AF and aperture action, allthough AF is not really necessary (I do mainly MF on macro)