This is my second maro lens. First was Canon 60/2.8 macro, I used it with Canon 60D for 3 years.
What can I say about this lens? It's sharp like 60/2.8 (I don't see big difference in picture resolution, but at f/2.8, 100/2.8 IS is sharper; 100/2.8 IS on 60D is worse than 60/2.8, so this is not good lens for aps-c in my opinion), it has IS and it's weather sealed. Video quality is much more better. On 60D videos are more blurred and there's a low level of moire.
Lens is very good, but I don't like noisy IS. I have a Tamron 24-70/2.8 VC and it's more silent in my videos. AF works fine, but it's very slow in the low light conditions.
There's a lot of reviews of this lens and my english is not good enough, so check my photos and videos ;)
Video (max quality, ALL - I, 30 fps):