Context: Lens released 2009. Like most of my lenses, I have sold this one. I used the lens from about 2012 to 2016.
This is a great lens but I had to sell it. If it had an aperture of 2.0 I probably would have kept it. Being a 2.8, I had to decide between keeping this, and keeping my old 70-200 2.8 IS, and I kept the 70-200 because it was overall more useful (because of the 200mm) and I don’t often shoot macros. The 100mm is great as a general walk-about and travel lens. It’s so much lighter than the 70-200. The IS is much quieter in the 100mm macro than it is on the old 70-200, so the 100 is better for shooting video for that reason.
Image quality: Excellent.
Practical? Yes. This is an inconspicuous, light lens to carry around – compared to other lenses of this caliber.
Macro: I think technically this is not a macro since it is approximately 0.5x, not 1.0x. But it is certainly handy do be able to take this lens travelling, sitting down in venues etc., and not have to worry about subjects being too close to focus on. However - unless macro shots are the primary subject of your photography - if you have an 85mm f1.4, your 100mm 2.8 is unlikely to get much use.