I shoot doc video with a T3i. I just purchased a refurbished EF 16-35mm f/2.8L II direct from Canon.
The barrel, optics, AF and electronics seem flawless according to my first run-through, but the zoom ring is VERY tight, significantly moreso than any other zoom lens I've used. I tried a buddy's 24-105mm f/4, and it was much easier to move.
No dealer in my area (Chattanooga) has this lens in stock, so I can't put my hands on another one exactly like mine to compare.
I called Canon tech support (very, very friendly BTW), and they said it sounds normal to them, especially for a fast UWA zoom which has to move some big elements around in there.
The operation is smooth, but it just really takes a grip and twist to move it. I want to believe that the tight fit just means I have an exceptionally high-tolerance lens, but I'm worried it may mean trouble later.
I REALLY need this lens; it's the only zoom that gets reasonably wide on an APS-C camera. I also love the image quality. But with only a 90-day warranty, I want to make sure this one doesn't have a birth defect.