I don’t normally go and rush out and preorder the new thing when it just comes out. I usually wait for others to get it and test it all out. But when Canon announced this lens I just could not resist, as I could get it at a great price. Also I wished and hoped for Canon to put out a wide angle zoom with IS and good IQ for while a while, and I needed to put my money where my mouth is. I use the IS more than F2.8 at the wider angles, as If I need more light, I usually use my 35 F1.4 and take a step back. So what is it like? Well I just got it today, and only had a few hours with it, but so far so good. Here it is next to the 16-35 F2.8 II. It is actually lighter than you might think for something that is a bit longer and larger than the 16-35 F2.8 II. The lens hood is MUCH smaller, and it fits into my shooting bag much better. Build quality is every bit as good as the 2.8. One huge benefit for me is that it uses 77 mm filters instead of the 82 of the 2.8 so I can use the same filters on all my lenses. LOVE THAT!!! Here is a quick test. 5D Mark III, ISO 640, 16mm, F8.0, 1/160. Handheld with IS on. Center Crop: Corner crop: I think It looks pretty good so far. From what I can see CA seems to be pretty well controlled as well. Weather permitting I will probably go for a walk around the city on the weekend to test it out a bit more. If you are in Melb, and want to come along feel free to PM me.