The focussing is absolutely lightning, I'm not sure what the poster before was talking about!
The Canon one is good in general. But to say it's slow focusing would be a huge understatement. There's no way I could use it for portraits, it's just not quick enough to focus.
Well mine is certainly not slow to focus I have used it for close up portraits with no problems
It's fine for adults that aren't moving in my experience (very good in fact) but hopeless for kids that are moving and I shoot quite a lot of kids. 70-200 is perfect so I don't mind leaving the 100mm in the bag for those shots.
Anyway, OP enjoy the lens, don't let my ranting about AF speed put you off it!