Lenses

Build quality
Optical quality
Value for money
Overall

Cons: Not so sharp till f2.8 Not so fast in bad light conditions, multiple focusing errors take place

Pros: Fast, amazingly fast in good light conditions, it feels like it at least twice as fast as my Canon 70-200/2.8L Picture quality outstanding Dust & moisture protection

Summary: Very good. PS Using with 5DMkII

Build quality
Optical quality
Value for money
Overall

Cons: price ($$$), as with any prime zoom is in my legs, so sometimes when I can't reach my subject I end up cropping the image afterwards, on a crop body APS-C this is a 38mm so I don't get that wide angle effect like on a FF, but I don't mind that (some people might, so I included this), weight... its not that bad, but if you are carrying this all day you do notice it, the front element is quite big and it does attract some attention (I don't particularly like that, so I include this in the cons), ahhhh one more thing... when you use the provided hood, forget about using on board flash (40D and 7D) hood throws a shadow on the scene (remove the hood and flash is useful again)

Pros: f1.4... amazing... really, I'm addicted :) VERY SHARP edge to edge on my 40D and now my 7D, no problems with chromatic aberrations in the corners, full weather sealing (I installed a front filter as soon as I got the lens), lens hood is included with this one, silent and smooth focus, accurate on both 40D and 7D, sometimes a bit too slow in dim lighting conditions (but no complaints on my part, to be expected), the lens has that 'pro' feel to it, AF/MF button works smoothly, and the MF ring is build to last, I feel that the lens is build better than my 40D and 7D so I am more worried about breaking the body then the lens :)

Summary: this is a pricy lens, no way to get around that, but you DO get what you pay for here, just make sure this is what you really want because there are other very good options out there that might suit you just fine (16-35 f2.8L II is in the same price range and if you don't really need that f1.4 go for that... on 2nd thought I might have as well, but what's done is done, I'll stick with this lens now that I'm getting used to it). I use this mainly for landscape photography and I am very pleased with the results. See what you think: http://www.flickr.com/photos/75328858@N04/6831043481/in/photostream but this would make an excellent video lens as well, the 38mm coverage on the APS-C body seems just right. The f1.4 definitely comes in useful in low light situations, but then again the ISO performance of the 7D is quite good... so you might not need that f1.4 after all (personal preference, so you have to decide) I give this lens 5 for build quality (EXCELLENT), 5 for optical quality (best I have ever owned), but 4 for 'value for money' just because of the price... I think that most people would be happier with the 16-35 f2.8L version I or II (I do miss that zoom sometimes)

Build quality
Optical quality
Value for money
Overall

Cons: 1

Pros: 1

Summary: 1