Shooting wide open (2.5) there may be a little blur around the edges. One stop or more down (3.2+) the lens is great. It's amazing how sharp this lens can get for under $400.00. With 6MP you can get down the individual pixel.
Recommend this product?
Autofocus is poor in low-light situations. When usable, it is slow but accurate. Nominal distortion from the lens itself, very important for a macro lens. Manual focus is easy when necessary.
In addition to a macro lens, this is also a good general purpose 50mm lens provided you don't need the 1.4, 2.0 stops and don't mind slightly slower than normal autofocus.