This is probably Canon’s most versatile lens in their lineup. It takes 1:1 macros, great focal length for portraits and nice compact short tele. It prrobably one of if not the sharpest lenses. Beautiful color and nice bokeh… not as nice as teh 85L but pretty nice. It’s also a fraction of the price. The USM version really makes it usable for portraits and even some action shots. There is a delimiter switch that really speeds things up if you don’t need to go to 1:1.
One big surprise is how much I like this lens for portraits. It lets me get really close and play with some creative framing. When “The Shot” reality TV show was on, I noticed a lot of the fashion photographers choose the 100 macro as opposed to the 85L, 100 f/2 or 85 f/1.8. Interesting but I guess not that big of a surprise.