Makes me want to try and photograph my eye. If only I had a proper macro lens. I was thinking of getting one of these after seeing a video showing how awesome it is, has anyone here used this particular lens before?
^ You're probably better off popping that model into google and reading forum-based user reviews/comments.
Pretty much every brand-name lens has got plenty of forum threads around the place comparing it to similar cheaper or more expensive lenses in terms of sharpness, speed, auto-focusing ability/speed/noise, chromatic distortion, etc.