Fisheye question

[45R]

I've been reading really good reviews about the Sigma 15mm F/2.8 fisheye. The consensus is that the lens is sharp. I've been shooting mine on and off since December and the images that come out of this lens has been really soft. Could anyone be nice enough to post a few pictures for comparision. I called Sigma and the guy behind the phone line was not very helpful and asked me to call back in the AM when he had 1/2 hour left on his shift. :T

Thanks in advanced.