I was a little worried about this lens before I bought it, I had fancied a fisheye for years but couldn't bring myself to part with the £600 or so for a Cannon or Sigma lens. I came across this after reading about it in a magazine and at first was a little worried about it being a manual lens. However, set the Aperture to 8 and the focus to infinity and every single picture you take will be pin sharp. It works ok in very low light but really excells at wide open shots with foreground interest.
It is very solid, well made and simple to use, the detachable hood is a bonus over the older model and the price is superb.
This lens opens up a whole new world of photography, buy it!