As the title states, I am looking for a good 70-200mm zoom lens. I currently have a Canon 28-125mm IS zoom, thats as far as my zoom capability goes right now on my T1i. I've been reading reviews of the two different lenses and it seems the Sigma has more cons, as you can't go wrong with an "L" apparently. New from B&H the Sigma 70-200mm f 2.8 II EX DG HSM will go for $799. Several of the reviews state it can make soft shots and most reviews state CA will show up when zooming in. Also, some intermittent reviews state it has problems with front-focusing. However, quite a few people are happy with its price/performance ratio. The f/2.8 would be awesome, the price is good compared to the Canon version, but I'm wary of the cons that some reviewers have brought up. The Canon 70-200mm f/4 L can be had for like $500-$550 used in great condition. I've never read a bad review on it, I'm not even really aware of any cons for this glass, as users write nothing but good stuff about it. The only drawback I can see is the f/4, other than that, nothing bad. Price is great. Has anyone else had to decide between these two lenses? I know I've pretty much justified the Canon, but wanted to hear if anyone else has decided between these two.