There are loads of threads on these on the forum. Just do a search for it.
IMO its the sharpest lens Ive ever owned. Far sharper than the Nikon 85mm f/1.8, even at f/1.4.
All samyangs are manual focus only, but get an AE version to get aperture control through the camera.
Lots of photos here of it and from it.
http://www.flickr.com/photos/tcr4x4/sets/72157626167924003/