Just a quick one really, can someone who has both or someone who has one of either post their views? hates? likes? etc. The sigma is just over £100 more expensive and has 2.8 but whether the 2.8 is sharp from 70-200 is another matter whereas I know the L is sharp at f4 at all zooms but obviously slower because ...well only f4 :/ Will be ordering one or the other along with a 17-40L (with a uv to keep the dust maggots out!!) this month sometime ¬_¬ Taa!