And to add more detail, the length gives you quite a bit of versatility, not only is it a good macro lens, but it's good for gigs as it has a bit of range for close-up-ish shots, and gives you good bokeh for non-macro but close shots of things, IE, portraits etc.
This was taken using Helicon Focus to stack together about 20 photos taken with the 100mm to get the whole image in focus and pretty sharp...
Lucanus cervus 1 by
Chris_Moody, on Flickr