I have had this lens for about a year now and must admit it has far outreached my expectations. I wanted a close up lens for nature photography and have found this little baby exceptional - so long as the camera is on a tripod the crispness of the photos is remarkable. For a macro close up lens this really does a great job and for that alone I would give 5 stars. However, as a portrait lens it is amazing. Colour balance and optical clarity is as good as a Canon lens, so considering that I only bought this lens for macro work, I feel I have really struck gold.
I am from the old school of film, manual settings and focussing, long evenings in my smelly dark room, long waits for colour prints and so much disappointment at wrong settings etc. This digital age is amazing and no way would I go back to 'good old film' and all that it entails. Having this lens on my Canon EOS30D is a marriage made in heaven. It also brings out the photographer in me once again, simply by being fixed, as opposed to zoom, it means I have to use my feet to find the right spot, causing me to take more care and time both framing and setting depth of field before I begin to press that shutter.
So there you have it. A brilliant macro lens and a superb portrait lens rolled into one.
UPDATE: 23rd January 21013
Last year I updated my EOS 30D to an EOS 50D and have to say that this lens and camera combination has allowed me to get some exceptional shots. As a macro lens some of my bumble bee and hover fly shots have exceeded all my expectations. I have used this lens for thousands of shots and can honesty say it is my most used and favourite lens and continues to come up with some fantastic photographs. My best lens ever, to my mind almost as good as an 'L' lens.