To the poster above, "Comparable with the 1.4/35L!" is quite wrong, I don't know how you could even post that a 14L would be as sharp as the 35L, that's almost an insult to the intelligence of the people around here. These reviews above mine do not accurately portray this lens based on my experience, and after seeing so many people having the same experience as me online.
The corners of this lens are soft, especially at 2.8. You almost have to stop it down to F8 to get good performance across the frame unless you want your trees to look like mashed potatoes.
I took this lens out and was shooting lots of beach stuff tripod mounted, fired off with cable release, and the sand was barely resolved. So, I put my 24L on, and BAM, tack sharp--no CA.....whereas the 14L was soft and had CA all along the highlights.
When you pay over $2,000 for a lens, you would hope that it would not be bested at the same focal length by a Nikon zoom. The new Nikon 14-24G destroys this lens and only costs $1,700. Canon needs to get their act to together. I sent my lens back, it's not worth the money in my opinion.