Compared to the 16-35mm f/2.8 lens, this one is much more affordable. It has the same minimum focal distance of eleven inches, and is a few ounces lighter than the 16-35mm.
I will complain that the lens is not as sharp as I would expect from an "L" lens, even when stopped down to f/11 or smaller. Also, the EW-83E lens hood does almost nothing for the image quality in my experience. It is very wide and very short, and really doesn't even protect the lens much. I often have to use my hand to block the sun flares even when the hood is on.
As far as uses go I would recommend it as a general-purpose lens if you can deal with the unsharp factor, especially if you are using it on a crop-sensor camera. It is mostly used for landscapes and architecture. I have used it for portraits on occasion, but I often have to sharpen the image to feel satisfied with the outcome - especially if using it at f/5.6 or smaller. Also, it is not good for head shots because of the distortion, as it is an ultra-wide lens. It's really best to just invest in a portrait lens if you are photographing people.